diff --git a/squashfs_override/usr/lib/python2.7/dist-packages/Registry/Registry.py b/squashfs_override/usr/lib/python2.7/dist-packages/Registry/Registry.py
index 47b719e..4288ed0 100644
--- a/squashfs_override/usr/lib/python2.7/dist-packages/Registry/Registry.py
+++ b/squashfs_override/usr/lib/python2.7/dist-packages/Registry/Registry.py
@@ -66,7 +66,7 @@ def __init__(self, value):
         super(RegistryKeyHasNoParentException, self).__init__(value)
 
     def __str__(self):
-        return "Registry key has no parent key: %s" % (self._value)
+        return f"Registry key has no parent key: {self._value}"
 
 
 class RegistryKeyNotFoundException(RegistryParse.RegistryStructureDoesNotExist):
@@ -81,7 +81,7 @@ def __init__(self, value):
         super(RegistryKeyNotFoundException, self).__init__(value)
 
     def __str__(self):
-        return "Registry key not found: %s" % (self._value)
+        return f"Registry key not found: {self._value}"
 
 class RegistryValueNotFoundException(RegistryParse.RegistryStructureDoesNotExist):
     """
@@ -95,7 +95,7 @@ def __init__(self, value):
         super(RegistryValueNotFoundException, self).__init__(value)
 
     def __str__(self):
-        return "Registry value not found: %s" % (self._value)
+        return f"Registry value not found: {self._value}"
 
 class RegistryValue(object):
     """
@@ -111,10 +111,7 @@ def name(self):
         Get the name of the value as a string.
         The name of the default value is returned as "(default)".
         """
-        if self._vkrecord.has_name():
-            return self._vkrecord.name()
-        else:
-            return  "(default)"
+        return self._vkrecord.name() if self._vkrecord.has_name() else "(default)"
 
     def value_type(self):
         """
@@ -273,8 +270,8 @@ def value(self, name):
                 if v.name().lower() == name.lower():
                     return RegistryValue(v)
         except RegistryParse.RegistryStructureDoesNotExist:
-            raise RegistryValueNotFoundException(self.path() + " : " + name)
-        raise RegistryValueNotFoundException(self.path() + " : " + name)
+            raise RegistryValueNotFoundException(f"{self.path()} : {name}")
+        raise RegistryValueNotFoundException(f"{self.path()} : {name}")
 
     def find_key(self, path):
         """
diff --git a/squashfs_override/usr/lib/python2.7/dist-packages/Registry/RegistryParse.py b/squashfs_override/usr/lib/python2.7/dist-packages/Registry/RegistryParse.py
index e5e9a56..f9f27f4 100644
--- a/squashfs_override/usr/lib/python2.7/dist-packages/Registry/RegistryParse.py
+++ b/squashfs_override/usr/lib/python2.7/dist-packages/Registry/RegistryParse.py
@@ -64,7 +64,7 @@ def __init__(self, value):
         self._value = value
 
     def __str__(self):
-        return "Registry Exception: %s" % (self._value)
+        return f"Registry Exception: {self._value}"
 
 
 class RegistryStructureDoesNotExist(RegistryException):
@@ -82,7 +82,7 @@ def __init__(self, value):
         super(RegistryStructureDoesNotExist, self).__init__(value)
 
     def __str__(self):
-        return "Registry Structure Does Not Exist Exception: %s" % (self._value)
+        return f"Registry Structure Does Not Exist Exception: {self._value}"
 
 
 class ParseException(RegistryException):
@@ -99,7 +99,7 @@ def __init__(self, value):
         super(ParseException, self).__init__(value)
 
     def __str__(self):
-        return "Registry Parse Exception(%s)" % (self._value)
+        return f"Registry Parse Exception({self._value})"
 
 
 class UnknownTypeException(RegistryException):
@@ -129,7 +129,7 @@ def __init__(self, value):
         super(UnknownTypeException, self).__init__(value)
 
     def __str__(self):
-        return "Unknown Type Exception(%s)" % (self._value)
+        return f"Unknown Type Exception({self._value})"
 
 
 class RegistryBlock(object):
@@ -163,7 +163,7 @@ def unpack_word(self, offset):
         Arguments:
         - `offset`: The relative offset from the start of the block.
         """
-        return struct.unpack_from(str("<H"), self._buf, self._offset + offset)[0]
+        return struct.unpack_from("<H", self._buf, self._offset + offset)[0]
 
     def unpack_dword(self, offset):
         """
@@ -171,7 +171,7 @@ def unpack_dword(self, offset):
         Arguments:
         - `offset`: The relative offset from the start of the block.
         """
-        return struct.unpack_from(str("<I"), self._buf, self._offset + offset)[0]
+        return struct.unpack_from("<I", self._buf, self._offset + offset)[0]
 
     def unpack_int(self, offset):
         """
@@ -179,7 +179,7 @@ def unpack_int(self, offset):
         Arguments:
         - `offset`: The relative offset from the start of the block.
         """
-        return struct.unpack_from(str("<i"), self._buf, self._offset + offset)[0]
+        return struct.unpack_from("<i", self._buf, self._offset + offset)[0]
 
     def unpack_qword(self, offset):
         """
@@ -187,7 +187,7 @@ def unpack_qword(self, offset):
         Arguments:
         - `offset`: The relative offset from the start of the block.
         """
-        return struct.unpack_from(str("<Q"), self._buf, self._offset + offset)[0]
+        return struct.unpack_from("<Q", self._buf, self._offset + offset)[0]
 
     def unpack_string(self, offset, length):
         """
@@ -196,7 +196,7 @@ def unpack_string(self, offset, length):
         - `offset`: The relative offset from the start of the block.
         - `length`: The length of the string.
         """
-        return struct.unpack_from(str("<%ds") % (length), self._buf, self._offset + offset)[0]
+        return struct.unpack_from("<%ds" % length, self._buf, self._offset + offset)[0]
 
     def absolute_offset(self, offset):
         """
@@ -241,10 +241,6 @@ def __init__(self, buf, offset, parent):
         _seq1 = self.unpack_dword(0x4)
         _seq2 = self.unpack_dword(0x8)
 
-        if _seq1 != _seq2:
-            # the registry was not synchronized
-            pass
-
         # TODO: compute checksum and check
 
     def major_version(self):
@@ -325,10 +321,7 @@ def size(self):
         """
         Size of this cell, as an unsigned integer.
         """
-        if self.is_free():
-            return self._size
-        else:
-            return self._size * -1
+        return self._size if self.is_free() else self._size * -1
 
     def next(self):
         """
@@ -484,7 +477,7 @@ def large_data(self, length):
         while length > 0:
             off = self.abs_offset_from_hbin_offset(self.unpack_dword(4 * count))
             size = min(0x3fd8, length)
-            b += HBINCell(self._buf, off, self).raw_data()[0:size]
+            b += HBINCell(self._buf, off, self).raw_data()[:size]
 
             count += 1
             length -= size
@@ -541,16 +534,7 @@ def decode_utf16le(s):
     if b"\x00\x00" in s:
         index = s.index(b"\x00\x00")
         if index > 2:
-            if s[index - 2] != b"\x00"[0]: #py2+3 
-                #  61 00 62 00 63 64 00 00
-                #                    ^  ^-- end of string
-                #                    +-- index
-                s = s[:index + 2]
-            else:
-                #  61 00 62 00 63 00 00 00
-                #                 ^     ^-- end of string
-                #                 +-- index
-                s = s[:index + 3]
+            s = s[:index + 2] if s[index - 2] != b"\x00"[0] else s[:index + 3]
     if (len(s) % 2) != 0:
         s = s + b"\x00"
     s = s.decode("utf16")
@@ -610,22 +594,18 @@ def data_type_str(self):
         elif data_type == RegFileTime:
             return "RegFileTime"
         else:
-            return "Unknown type: %s" % (hex(data_type))
+            return f"Unknown type: {hex(data_type)}"
 
     def __str__(self):
-        if self.has_name():
-            name = self.name()
-        else:
-            name = "(default)"
-
+        name = self.name() if self.has_name() else "(default)"
         data = ""
         data_type = self.data_type()
-        if data_type == RegSZ or data_type == RegExpandSZ:
-            data = self.data()[0:16] + "..."
+        if data_type in [RegSZ, RegExpandSZ]:
+            data = f"{self.data()[:16]}..."
         elif data_type == RegMultiSZ:
-            data = str(len(self.data())) + " strings"
-        elif data_type == RegDWord or data_type == RegQWord:
-            data = str(hex(self.data()))
+            data = f"{len(self.data())} strings"
+        elif data_type in [RegDWord, RegQWord]:
+            data = hex(self.data())
         elif data_type == RegNone:
             data = "(none)"
         elif data_type == RegBin:
@@ -660,9 +640,8 @@ def name(self):
         """
         if not self.has_name():
             return ""
-        else:
-            name_length = self.unpack_word(0x2)
-            return self.unpack_string(0x14, name_length).decode("windows-1252")
+        name_length = self.unpack_word(0x2)
+        return self.unpack_string(0x14, name_length).decode("windows-1252")
 
     def data_type(self):
         """
@@ -703,23 +682,22 @@ def raw_data(self):
         data_offset = self.data_offset()
         ret = None
 
-        if data_type == RegSZ or data_type == RegExpandSZ:
+        if data_type in [RegSZ, RegExpandSZ]:
             if data_length >= 0x80000000:
                 # data is contained in the data_offset field
                 ret = self._buf[data_offset:data_offset + 0x4]
             elif 0x3fd8 < data_length < 0x80000000:
                 d = HBINCell(self._buf, data_offset, self)
-                if d.data_id() == b"db":
-                    # this should always be the case
-                    # but empirical testing does not confirm this
-                    ret = d.child().large_data(data_length)
-                else:
-                    ret = d.raw_data()[:data_length]
+                ret = (
+                    d.child().large_data(data_length)
+                    if d.data_id() == b"db"
+                    else d.raw_data()[:data_length]
+                )
             else:
                 d = HBINCell(self._buf, data_offset, self)
                 data_offset = d.data_offset()
                 ret = self._buf[data_offset:data_offset + data_length]
-        elif data_type == RegBin or data_type == RegNone:
+        elif data_type in [RegBin, RegNone]:
             if data_length >= 0x80000000:
                 data_length -= 0x80000000
                 ret = self._buf[data_offset:data_offset + data_length]
@@ -756,10 +734,12 @@ def raw_data(self):
             d = HBINCell(self._buf, data_offset, self)
             data_offset = d.data_offset()
             ret = self._buf[data_offset:data_offset + 4]
-        elif data_type == RegLink or \
-                        data_type == RegResourceList or \
-                        data_type == RegFullResourceDescriptor or \
-                        data_type == RegResourceRequirementsList:
+        elif data_type in [
+            RegLink,
+            RegResourceList,
+            RegFullResourceDescriptor,
+            RegResourceRequirementsList,
+        ]:
             if data_length >= 0x80000000:
                 data_length -= 0x80000000
                 ret = self._buf[data_offset:data_offset + data_length]
@@ -777,20 +757,16 @@ def raw_data(self):
             ret = self._buf[data_offset + 4:data_offset + 4 + data_length]
         elif data_length < 5 or data_length >= 0x80000000:
             ret = self.unpack_binary(0x8, 4)
-        else:
-            if data_length >= 0x80000000:
-                data_length -= 0x80000000
-                ret = self._buf[data_offset:data_offset + data_length]
-            elif 0x3fd8 < data_length < 0x80000000:
-                d = HBINCell(self._buf, data_offset, self)
-                if d.data_id() == b"db":
-                    # this should always be the case
-                    # but empirical testing does not confirm this
-                    ret = d.child().large_data(data_length)
-                else:
-                    ret = d.raw_data()[:data_length]
+        elif 0x3FD8 < data_length < 0x80000000:
+            d = HBINCell(self._buf, data_offset, self)
+            if d.data_id() == b"db":
+                # this should always be the case
+                # but empirical testing does not confirm this
+                ret = d.child().large_data(data_length)
             else:
-                ret = self._buf[data_offset + 4:data_offset + 4 + data_length]
+                ret = d.raw_data()[:data_length]
+        else:
+            ret = self._buf[data_offset + 4:data_offset + 4 + data_length]
         return ret
 
     def data(self):
@@ -831,30 +807,32 @@ def data(self):
         data_length = self.raw_data_length()
         d = self.raw_data()
 
-        if data_type == RegSZ or data_type == RegExpandSZ:
+        if data_type in [RegSZ, RegExpandSZ]:
             return decode_utf16le(d)
-        elif data_type == RegBin or data_type == RegNone:
+        elif data_type in [RegBin, RegNone]:
             return d
         elif data_type == RegDWord:
-            return struct.unpack_from(str("<I"), d, 0)[0]
+            return struct.unpack_from("<I", d, 0)[0]
         elif data_type == RegMultiSZ:
             s = d.decode("utf16")
             return s.split("\x00")
         elif data_type == RegQWord:
-            return struct.unpack_from(str("<Q"), d, 0)[0]
+            return struct.unpack_from("<Q", d, 0)[0]
         elif data_type == RegBigEndian:
-            return struct.unpack_from(str(">I"), d, 0)[0]
-        elif data_type == RegLink or \
-                        data_type == RegResourceList or \
-                        data_type == RegFullResourceDescriptor or \
-                        data_type == RegResourceRequirementsList:
+            return struct.unpack_from(">I", d, 0)[0]
+        elif data_type in [
+            RegLink,
+            RegResourceList,
+            RegFullResourceDescriptor,
+            RegResourceRequirementsList,
+        ]:
             # we don't really support these types, but can at least
             #  return raw binary for someone else to work with.
             return d
         elif data_type == RegFileTime:
             return parse_windows_timestamp(d)
         elif data_length < 5 or data_length >= 0x80000000:
-            return struct.unpack_from(str("<I"), d, 0)[0]
+            return struct.unpack_from("<I", d, 0)[0]
         else:
             raise UnknownTypeException("Unknown VK Record type 0x%x at 0x%x" % (data_type, self.offset()))
 
@@ -912,7 +890,7 @@ def values(self):
         """
         value_item = 0x0
 
-        for _ in range(0, self._number):
+        for _ in range(self._number):
             value_offset = self.abs_offset_from_hbin_offset(self.unpack_dword(value_item))
 
             d = HBINCell(self._buf, value_offset, self)
@@ -977,13 +955,12 @@ def keys(self):
         """
         key_index = 0x4
 
-        for _ in range(0, self._keys_len()):
+        for _ in range(self._keys_len()):
             key_offset = self.abs_offset_from_hbin_offset(self.unpack_dword(key_index))
             d = HBINCell(self._buf, key_offset, self)
 
             try:
-                for k in d.child().keys():
-                    yield k
+                yield from d.child().keys()
             except RegistryStructureDoesNotExist:
                 raise ParseException("Unsupported subkey list encountered.")
 
@@ -1011,7 +988,7 @@ def keys(self):
         """
         key_index = 0x4
 
-        for _ in range(0, self._keys_len()):
+        for _ in range(self._keys_len()):
             key_offset = self.abs_offset_from_hbin_offset(self.unpack_dword(key_index))
 
             d = HBINCell(self._buf, key_offset, self)
@@ -1044,7 +1021,7 @@ def keys(self):
         """
         key_index = 0x4
 
-        for _ in range(0, self._keys_len()):
+        for _ in range(self._keys_len()):
             key_offset = self.abs_offset_from_hbin_offset(self.unpack_dword(key_index))
 
             d = HBINCell(self._buf, key_offset, self)
@@ -1153,7 +1130,13 @@ def classname(self):
 
         offset = self.abs_offset_from_hbin_offset(classname_offset)
         d = HBINCell(self._buf, offset, self)
-        return struct.unpack_from(str("<%ds") % (classname_length), self._buf, d.data_offset())[0].decode("utf-16le").rstrip("\x00")
+        return (
+            struct.unpack_from(
+                "<%ds" % classname_length, self._buf, d.data_offset()
+            )[0]
+            .decode("utf-16le")
+            .rstrip("\x00")
+        )
 
     def timestamp(self):
         """
@@ -1226,9 +1209,7 @@ def values_number(self):
         Get the number of values associated with this NKRecord/Key.
         """
         num = self.unpack_dword(0x24)
-        if num == 0xFFFFFFFF:
-            return 0
-        return num
+        return 0 if num == 0xFFFFFFFF else num
 
     def values_list(self):
         """
@@ -1248,9 +1229,7 @@ def subkey_number(self):
         Get the number of subkeys of this key.
         """
         number = self.unpack_dword(0x14)
-        if number == 0xFFFFFFFF:
-            return 0
-        return number
+        return 0 if number == 0xFFFFFFFF else number
 
     def subkey_list(self):
         """
@@ -1275,7 +1254,9 @@ def subkey_list(self):
         elif id_ == b"li":
             l = LIRecord(self._buf, d.data_offset(), self)
         else:
-            raise ParseException("Subkey list with type %s encountered, but not yet supported." % (id_))
+            raise ParseException(
+                f"Subkey list with type {id_} encountered, but not yet supported."
+            )
 
         return l
 
diff --git a/squashfs_override/usr/lib/python2.7/dist-packages/davos/__init__.py b/squashfs_override/usr/lib/python2.7/dist-packages/davos/__init__.py
index 8ee12b2..00d00f8 100644
--- a/squashfs_override/usr/lib/python2.7/dist-packages/davos/__init__.py
+++ b/squashfs_override/usr/lib/python2.7/dist-packages/davos/__init__.py
@@ -124,12 +124,9 @@ def getKernelParams(self):
         with open('/proc/cmdline', 'r') as f:
             cmd_line = f.read().strip()
             for item in cmd_line.split(' '):
-                if '=' in item:
-                    key, value = item.split('=')
-                else:
-                    key, value = item, None
+                key, value = item.split('=') if '=' in item else (item, None)
                 self.kernel_params[key] = value
-        
+
         self.logger.debug('Got kernel params %s', str(self.kernel_params))
 
 
@@ -162,8 +159,8 @@ def getHostInfo(self):
         self.hostname = self.host_data['shortname']
         # Setting env and machine hostname (for inventory)
         os.environ['HOSTNAME'] = self.hostname
-        self.runInShell('hostname ' + self.hostname)
-        self.runInShell('sed -i "s/debian/' + self.hostname + '/" /etc/hosts')
+        self.runInShell(f'hostname {self.hostname}')
+        self.runInShell(f'sed -i "s/debian/{self.hostname}/" /etc/hosts')
 
         self.logger.info('Got hostname: %s', self.hostname)
 
@@ -193,7 +190,9 @@ def mountNFSShares(self):
             os.makedirs(local_dir)
         if self.isEmptyDir(local_dir):
             self.logger.info('Mounting %s NFS Share', local_dir)
-            o, e, ec = self.runInShell('mount %s:%s %s' % (server, self.nfs_share_masters, local_dir))
+            o, e, ec = self.runInShell(
+                f'mount {server}:{self.nfs_share_masters} {local_dir}'
+            )
             if ec != 0:
                 self.logger.error('Cannot mount %s Share', local_dir)
                 self.logger.error('Output: %s', e)
@@ -204,7 +203,9 @@ def mountNFSShares(self):
             os.mkdir(local_dir)
         if self.isEmptyDir(local_dir):
             self.logger.info('Mounting %s NFS Share', local_dir)
-            o, e, ec = self.runInShell('mount %s:%s %s' % (server, self.nfs_share_postinst, local_dir))
+            o, e, ec = self.runInShell(
+                f'mount {server}:{self.nfs_share_postinst} {local_dir}'
+            )
             if ec != 0:
                 self.logger.error('Cannot mount %s Share', local_dir)
                 self.logger.error('Output: %s', e)
@@ -238,7 +239,9 @@ def confirm(self,response):
         """
         answer = ""
         while answer not in ["y", "n"]:
-            answer = raw_input("You have entered %s. Is this correct [Y/N]? " % response).lower()
+            answer = raw_input(
+                f"You have entered {response}. Is this correct [Y/N]? "
+            ).lower()
         return answer == "y"
 
     def setHostname(self):
@@ -253,9 +256,9 @@ def setHostname(self):
                     self.hostname = machinename
                     break
             else:
-                print("The hostname %s entered is not valid." % machinename)
+                print(f"The hostname {machinename} entered is not valid.")
         # Setting hostname
         self.logger.info('Setting hostname: %s', self.hostname)
         os.environ['HOSTNAME'] = self.hostname
-        self.runInShell('hostname ' + self.hostname)
-        self.runInShell('sed -i "s/debian/' + self.hostname + '/" /etc/hosts')
+        self.runInShell(f'hostname {self.hostname}')
+        self.runInShell(f'sed -i "s/debian/{self.hostname}/" /etc/hosts')
diff --git a/squashfs_override/usr/lib/python2.7/dist-packages/davos/dialog.py b/squashfs_override/usr/lib/python2.7/dist-packages/davos/dialog.py
index f5aa4ad..a15cee3 100644
--- a/squashfs_override/usr/lib/python2.7/dist-packages/davos/dialog.py
+++ b/squashfs_override/usr/lib/python2.7/dist-packages/davos/dialog.py
@@ -84,12 +84,12 @@ class error(Exception):
     def __init__(self, message=None):
         self.message = message
     def __str__(self):
-        return "<%s: %s>" % (self.__class__.__name__, self.message)
+        return f"<{self.__class__.__name__}: {self.message}>"
     def complete_message(self):
         if self.message:
-            return "%s: %s" % (self.ExceptionShortDescription, self.message)
+            return f"{self.ExceptionShortDescription}: {self.message}"
         else:
-            return "%s" % self.ExceptionShortDescription
+            return f"{self.ExceptionShortDescription}"
     ExceptionShortDescription = "pythondialog generic exception"
 
 # For backward-compatibility
@@ -248,11 +248,7 @@ class UnableToCreateTemporaryDirectory(error):
 
 def _simple_option(option, enable):
     """Turn on or off the simplest dialog Common Options."""
-    if enable:
-        return (option,)
-    else:
-        # This will not add any argument to the command line
-        return ()
+    return (option, ) if enable else ()
 
 
 def _find_in_path(prog_name):
@@ -583,7 +579,7 @@ def __init__(self, dialog="dialog", DIALOGRC=None, compat="dialog",
         # even read them), but it is a bit late, now. So, we set them
         # based on the (global) _dialog_exit_status_vars.keys.
         for var in _dialog_exit_status_vars.keys():
-            varname = "DIALOG_" + var
+            varname = f"DIALOG_{var}"
             setattr(self, varname, _dialog_exit_status_vars[var])
 
         self._dialog_prg = _path_to_executable(dialog)
@@ -591,11 +587,7 @@ def __init__(self, dialog="dialog", DIALOGRC=None, compat="dialog",
         self.dialog_persistent_arglist = []
 
         # Use stderr or stdout?
-        if self.compat == "Xdialog":
-            # Default to stdout if Xdialog
-            self.use_stdout = True
-        else:
-            self.use_stdout = False
+        self.use_stdout = self.compat == "Xdialog"
         if use_stdout != None:
             # Allow explicit setting
             self.use_stdout = use_stdout
diff --git a/squashfs_override/usr/lib/python2.7/dist-packages/davos/image_restorer.py b/squashfs_override/usr/lib/python2.7/dist-packages/davos/image_restorer.py
index 4a85437..8cdf5aa 100644
--- a/squashfs_override/usr/lib/python2.7/dist-packages/davos/image_restorer.py
+++ b/squashfs_override/usr/lib/python2.7/dist-packages/davos/image_restorer.py
@@ -41,19 +41,22 @@ def __init__(self, manager, mode):
 
     @property
     def available_images(self):
-        images = []
-        for d in os.listdir('/home/partimag'):
-            if os.path.isfile('/home/partimag/%s/davosInfo.json' % d):
-                images.append(d)
-        return images
+        return [
+            d
+            for d in os.listdir('/home/partimag')
+            if os.path.isfile(f'/home/partimag/{d}/davosInfo.json')
+        ]
 
     def select_image(self):
         def _get_title(image_uuid):
             try:
-                _json = json.loads(open('/home/partimag/%s/davosInfo.json' % image_uuid, 'r').read())
+                _json = json.loads(
+                    open(f'/home/partimag/{image_uuid}/davosInfo.json', 'r').read()
+                )
                 return _json['title']
             except:
                 return image_uuid
+
         available_images = self.available_images
         d = Dialog(dialog="dialog")
         choices = [(str(available_images.index(x) + 1), _get_title(x)) for x in available_images]
@@ -68,12 +71,12 @@ def _get_title(image_uuid):
     def check_image(self):
 
         # Check if the image exists or not
-        if not os.path.isdir('/home/partimag/' + self.image_uuid):
+        if not os.path.isdir(f'/home/partimag/{self.image_uuid}'):
             d = Dialog(dialog="dialog")
             d.msgbox("Could not find image on server", backtitle="Pulse Imaging Client")
             raise Exception('Could not find image on server')
         # Check if image is compatible (davos)
-        if not os.path.isfile('/home/partimag/%s/davosInfo.json' % self.image_uuid):
+        if not os.path.isfile(f'/home/partimag/{self.image_uuid}/davosInfo.json'):
             d = Dialog(dialog="dialog")
             d.msgbox("Selected image is not compatible with this backend, please convert this image to the correct format.", backtitle="Pulse Imaging Client")
             raise Exception('Could not find image on server')
@@ -102,9 +105,15 @@ def start(self):
 
         # Start the image restore
         if self.mode == 'multicast':
-            error_code = subprocess.call('yes 2>/dev/null| /usr/sbin/ocs-sr %s --mcast-port 2232 multicast_restoredisk %s %s 2>&1 1>/dev/null | tee /var/log/davos_restorer.log' % (self.manager.clonezilla_params['clonezilla_restorer_params'], self.image_uuid, self.device), shell=True)
+            error_code = subprocess.call(
+                f"yes 2>/dev/null| /usr/sbin/ocs-sr {self.manager.clonezilla_params['clonezilla_restorer_params']} --mcast-port 2232 multicast_restoredisk {self.image_uuid} {self.device} 2>&1 1>/dev/null | tee /var/log/davos_restorer.log",
+                shell=True,
+            )
         else:
-            error_code = subprocess.call('yes 2>/dev/null| /usr/sbin/ocs-sr %s restoredisk %s %s 2>&1 1>/dev/null | tee /var/log/davos_restorer.log' % (self.manager.clonezilla_params['clonezilla_restorer_params'], self.image_uuid, self.device), shell=True)
+            error_code = subprocess.call(
+                f"yes 2>/dev/null| /usr/sbin/ocs-sr {self.manager.clonezilla_params['clonezilla_restorer_params']} restoredisk {self.image_uuid} {self.device} 2>&1 1>/dev/null | tee /var/log/davos_restorer.log",
+                shell=True,
+            )
 
         # Save image JSON and LOG
         current_ts = time.strftime("%Y%m%d%H%M%S")
@@ -113,7 +122,7 @@ def start(self):
 
         if error_code != 0:
             self.logger.warning('An error was encountered while restoring image, check davos_restorer.log for more details.')
-            saver_log_path = os.path.join(image_dir, 'davos_restorer-%s.log' % (current_ts) )
+            saver_log_path = os.path.join(image_dir, f'davos_restorer-{current_ts}.log')
             open(saver_log_path, 'w').write(open('/var/log/davos_restorer.log', 'r').read())
             time.sleep(15)
 
diff --git a/squashfs_override/usr/lib/python2.7/dist-packages/davos/image_saver.py b/squashfs_override/usr/lib/python2.7/dist-packages/davos/image_saver.py
index 089747a..779b8cd 100644
--- a/squashfs_override/usr/lib/python2.7/dist-packages/davos/image_saver.py
+++ b/squashfs_override/usr/lib/python2.7/dist-packages/davos/image_saver.py
@@ -53,7 +53,10 @@ def start(self):
             self.device = 'vda'
 
         # Start the image saver
-        error_code = subprocess.call('yes 2>/dev/null|/usr/sbin/ocs-sr %s savedisk %s %s 2>&1 1>/dev/null | tee /var/log/davos_saver.log' % (self.manager.clonezilla_params['clonezilla_saver_params'], self.image_uuid, self.device), shell=True)
+        error_code = subprocess.call(
+            f"yes 2>/dev/null|/usr/sbin/ocs-sr {self.manager.clonezilla_params['clonezilla_saver_params']} savedisk {self.image_uuid} {self.device} 2>&1 1>/dev/null | tee /var/log/davos_saver.log",
+            shell=True,
+        )
 
         image_dir = os.path.join('/home/partimag/', self.image_uuid) + '/'
 
@@ -63,12 +66,18 @@ def start(self):
             open(saver_log_path, 'w').write(open('/var/log/davos_saver.log', 'r').read())
             time.sleep(15)
 
-        # Save image JSON and LOG
-        info = {}
         current_ts = time.strftime("%Y-%m-%d %H:%M:%S")
-        info['title'] = 'Image of %s at %s' % (self.manager.hostname, current_ts)
-        info['description'] = ''
-        info['size'] = sum(os.path.getsize(image_dir+f) for f in os.listdir(image_dir) if os.path.isfile(image_dir+f))
+        info = {
+            'title': f'Image of {self.manager.hostname} at {current_ts}',
+            'description': '',
+            'size': sum(
+                (
+                    os.path.getsize(image_dir + f)
+                    for f in os.listdir(image_dir)
+                    if os.path.isfile(image_dir + f)
+                )
+            ),
+        }
         info['has_error'] = (error_code == 0)
 
         log_path = os.path.join(image_dir, 'davos.log')
diff --git a/squashfs_override/usr/lib/python2.7/dist-packages/davos/inventory.py b/squashfs_override/usr/lib/python2.7/dist-packages/davos/inventory.py
index e4ecb98..a5a63ec 100644
--- a/squashfs_override/usr/lib/python2.7/dist-packages/davos/inventory.py
+++ b/squashfs_override/usr/lib/python2.7/dist-packages/davos/inventory.py
@@ -34,7 +34,7 @@ def __init__(self, manager):
         self.editNodeText('OSNAME', 'Unknown operating system (PXE network boot inventory)')
         self.editNodeText('FULL_NAME', 'Unknown operating system (PXE network boot inventory)')
         timestamp = time.ctime()
-        self.editNodeText('OSCOMMENTS', 'Inventory generated on ' + timestamp)
+        self.editNodeText('OSCOMMENTS', f'Inventory generated on {timestamp}')
 
         # If we have a detected OS, we inventory OS and SOFT
         #if self.OS:
@@ -42,9 +42,7 @@ def __init__(self, manager):
 
         # Find mac address of connected interface
         pnic = psutil.net_io_counters(pernic=True)
-        stats = {}
-        for nicname in list(pnic.keys()):
-            stats[nicname] = pnic[nicname].bytes_sent
+        stats = {nicname: pnic[nicname].bytes_sent for nicname in list(pnic.keys())}
         self.interface = max(stats, key=stats.get)
         sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
         info = fcntl.ioctl(sock.fileno(), 0x8927,  struct.pack('256s', self.interface[:15]))
@@ -60,11 +58,13 @@ def __init__(self, manager):
 
         # Copy file to inventories folder on tftp server
         self.logger.info('Uploading inventory to Pulse server')
-        filehandler = open('/tmp' + self.macaddress + '.xml', 'w')
-        filehandler.write(data)
-        filehandler.close()
+        with open(f'/tmp{self.macaddress}.xml', 'w') as filehandler:
+            filehandler.write(data)
         tftpclient = tftpy.TftpClient(manager.tftp_ip, 69)
-        tftpclient.upload('/' + manager.dump_path + '/' + self.macaddress + '.xml', '/tmp' + self.macaddress + '.xml')
+        tftpclient.upload(
+            f'/{manager.dump_path}/{self.macaddress}.xml',
+            f'/tmp{self.macaddress}.xml',
+        )
 
 
     @property
@@ -87,12 +87,10 @@ def windowsHandler(self):
         from Registry import Registry
         reg = Registry.Registry('/mnt/Windows/System32/config/SOFTWARE')
 
-        # ======== OS SECTION ===============================================
-
-        cv_dict = {}
-        for entry in reg.open('Microsoft\\Windows NT\\CurrentVersion').values():
-            cv_dict[entry.name()] = entry.value()
-
+        cv_dict = {
+            entry.name(): entry.value()
+            for entry in reg.open('Microsoft\\Windows NT\\CurrentVersion').values()
+        }
         if 'ProductName' in cv_dict:
             self.editNodeText('OSNAME', 'Microsoft ' + cv_dict['ProductName'])
             self.editNodeText('FULL_NAME', 'Microsoft ' + cv_dict['ProductName'])
@@ -127,11 +125,7 @@ def windowsHandler(self):
                 except:
                     soft_dict[entry.name()] = entry.value()
 
-            soft = {}
-            soft['ARCH'] = 'x86_64'
-            soft['FROM'] = 'registry'
-            soft['GUID'] = key.name()
-
+            soft = {'ARCH': 'x86_64', 'FROM': 'registry', 'GUID': key.name()}
             if 'HelpLink' in soft_dict:
                 soft['HELPLINK'] = soft_dict['HelpLink']
 
@@ -163,7 +157,7 @@ def addSoftware(self, data):
         cont = self.dom.getElementsByTagName('CONTENT')[0]
         softnode = self.dom.createElement('SOFTWARES')
         for k in ['ARCH', 'FROM', 'GUID', 'NAME', 'PUBLISHER', 'UNINSTALL_STRING', 'URL_INFO_ABOUT', 'VERSION']:
-            if not k in data:
+            if k not in data:
                 continue
             elem = self.dom.createElement(k)
             txt = self.dom.createTextNode(data[k])
diff --git a/squashfs_override/usr/lib/python2.7/dist-packages/davos/xmlrpc_client.py b/squashfs_override/usr/lib/python2.7/dist-packages/davos/xmlrpc_client.py
index c48b6d8..368e6e0 100644
--- a/squashfs_override/usr/lib/python2.7/dist-packages/davos/xmlrpc_client.py
+++ b/squashfs_override/usr/lib/python2.7/dist-packages/davos/xmlrpc_client.py
@@ -12,7 +12,7 @@ def __init__(self, ip):
         # Building url (dirty, port and protocol are hardcoded
         # but we are limited by grub command line max length
         # We could pass them if we upgrade to grub2
-        self.base_url = "https://%s:9990/" % ip
+        self.base_url = f"https://{ip}:9990/"
 
     def __getattr__(self, attr_name):
         # Return the corresponding api proxy according to attr
diff --git a/squashfs_override/usr/lib/python2.7/dist-packages/debconf.py b/squashfs_override/usr/lib/python2.7/dist-packages/debconf.py
index bdfeb36..fbba1dd 100644
--- a/squashfs_override/usr/lib/python2.7/dist-packages/debconf.py
+++ b/squashfs_override/usr/lib/python2.7/dist-packages/debconf.py
@@ -52,7 +52,7 @@ def __init__(self, title=None, read=None, write=None):
     def setUp(self, title):
         self.version = self.version(2)
         if self.version[:2] != '2.':
-            raise DebconfError(256, "wrong version: %s" % self.version)
+            raise DebconfError(256, f"wrong version: {self.version}")
         self.capabilities = self.capb().split()
         if title:
             self.title(title)
@@ -76,21 +76,15 @@ def command(self, command, *params):
                 else:
                     raise
 
-        if ' ' in resp:
-            status, data = resp.split(' ', 1)
-        else:
-            status, data = resp, ''
+        status, data = resp.split(' ', 1) if ' ' in resp else (resp, '')
         status = int(status)
         if status == 0:
             return data
-        elif status == 1:   # unescaped data
+        elif status == 1:
             unescaped = ''
             for chunk in re.split(r'(\\.)', data):
                 if chunk.startswith('\\') and len(chunk) == 2:
-                    if chunk[1] == 'n':
-                        unescaped += '\n'
-                    else:
-                        unescaped += chunk[1]
+                    unescaped += '\n' if chunk[1] == 'n' else chunk[1]
                 else:
                     unescaped += chunk
             return unescaped
diff --git a/squashfs_override/usr/lib/python2.7/dist-packages/enum.py b/squashfs_override/usr/lib/python2.7/dist-packages/enum.py
index 63f5026..3ae76a2 100644
--- a/squashfs_override/usr/lib/python2.7/dist-packages/enum.py
+++ b/squashfs_override/usr/lib/python2.7/dist-packages/enum.py
@@ -217,12 +217,13 @@ def __setitem__(self, index, value):
     def __delitem__(self, index):
         raise EnumImmutableError(index)
 
-    def __iter__(self):
-        return iter(self._values)
-
     def __contains__(self, value):
         is_member = False
-        if isinstance(value, basestring):
+        return (
+            (value in self._keys)
+            if isinstance(value, basestring)
+            else (value in self._values)
+        )
             is_member = (value in self._keys)
         else:
             is_member = (value in self._values)