diff --git a/plugins/VersionUpgrade/VersionUpgrade21to22/MachineInstance.py b/plugins/VersionUpgrade/VersionUpgrade21to22/MachineInstance.py
index e4f067b5f3..10eb3a0607 100644
--- a/plugins/VersionUpgrade/VersionUpgrade21to22/MachineInstance.py
+++ b/plugins/VersionUpgrade/VersionUpgrade21to22/MachineInstance.py
@@ -26,9 +26,9 @@ class MachineInstance:
     #   \param serialised A string with the contents of a machine instance file.
     def __init__(self, serialised):
         config = configparser.ConfigParser(interpolation = None)
-        config.read_string(serialised) #Read the input string as config file.
+        config.read_string(serialised) # Read the input string as config file.
 
-        #Checking file correctness.
+        # Checking file correctness.
         if not config.has_section("general"):
             raise SettingsError.InvalidFormatError("general")
         if not config.has_option("general", "version"):
@@ -37,7 +37,7 @@ class MachineInstance:
             raise SettingsError.InvalidFormatError("general/name")
         if not config.has_option("general", "type"):
             raise SettingsError.InvalidFormatError("general/type")
-        if int(config.get("general", "version")) != 1: #Explicitly hard-code version 1, since if this number changes the programmer MUST change this entire function.
+        if int(config.get("general", "version")) != 1: # Explicitly hard-code version 1, since if this number changes the programmer MUST change this entire function.
             raise SettingsError.InvalidVersionError("Version upgrade intermediary version 1")
 
         self._type_name = config.get("general", "type")
@@ -58,13 +58,13 @@ class MachineInstance:
     #   \return A serialised form of this machine instance, serialised in
     #   version 2 of the file format.
     def exportVersion2(self):
-        import VersionUpgrade21to22 #Import here to prevent circular dependencies.
-        config = configparser.ConfigParser(interpolation = None) #Build a config file in the form of version 2.
+        import VersionUpgrade21to22 # Import here to prevent circular dependencies.
+        config = configparser.ConfigParser(interpolation = None) # Build a config file in the form of version 2.
 
         config.add_section("general")
         config.set("general", "name", self._name)
         config.set("general", "type", self._type_name)
-        config.set("general", "version", "2") #Hard-code version 2, since if this number changes the programmer MUST change this entire function.
+        config.set("general", "version", "2") # Hard-code version 2, since if this number changes the programmer MUST change this entire function.
         if self._variant_name:
             config.set("general", "variant", self._variant_name)
         if self._key:
diff --git a/plugins/VersionUpgrade/VersionUpgrade21to22/Profile.py b/plugins/VersionUpgrade/VersionUpgrade21to22/Profile.py
index 8a461dad6a..c2eed5d47f 100644
--- a/plugins/VersionUpgrade/VersionUpgrade21to22/Profile.py
+++ b/plugins/VersionUpgrade/VersionUpgrade21to22/Profile.py
@@ -27,13 +27,13 @@ class Profile:
         parser = configparser.ConfigParser(interpolation = None)
         parser.read_string(serialised)
 
-        #Check correctness.
+        # Check correctness.
         if not parser.has_section("general"):
             raise SettingsError.InvalidFormatError("general")
         if not parser.has_option("general", "version") or int(parser.get("general", "version")) != 1: #Hard-coded profile version here. If this number changes the entire function needs to change.
             raise SettingsError.InvalidVersionError("Version upgrade intermediary version 1")
 
-        #Parse the general section.
+        # Parse the general section.
         self._name = parser.get("general", "name")
         self._type = parser.get("general", "type", fallback = None)
         if "weight" in parser["general"]:
@@ -50,13 +50,13 @@ class Profile:
         else:
             self._material_name = None
 
-        #Parse the settings.
+        # Parse the settings.
         self._settings = {}
         if parser.has_section("settings"):
             for key, value in parser["settings"].items():
                 self._settings[key] = value
 
-        #Parse the defaults and the disabled defaults.
+        # Parse the defaults and the disabled defaults.
         self._changed_settings_defaults = {}
         if parser.has_section("defaults"):
             for key, value in parser["defaults"].items():
@@ -73,11 +73,11 @@ class Profile:
     #   \return A serialised form of this profile, serialised in version 2 of
     #   the file format.
     def exportVersion2(self):
-        import VersionUpgrade21to22 #Import here to prevent circular dependencies.
+        import VersionUpgrade21to22 # Import here to prevent circular dependencies.
         config = configparser.ConfigParser(interpolation = None)
 
         config.add_section("general")
-        config.set("general", "version", "2") #Hard-coded profile version 2
+        config.set("general", "version", "2") # Hard-coded profile version 2
         config.set("general", "name", self._name)
         if self._type:
             config.set("general", "type", self._type)
@@ -107,7 +107,7 @@ class Profile:
         if self._disabled_settings_defaults:
             VersionUpgrade21to22.VersionUpgrade21to22.translateSettingNames(self._disabled_settings_defaults)
             config.add_section("disabled_defaults")
-            disabled_defaults_string = str(self._disabled_settings_defaults[0]) #Must be at least 1 item, otherwise we wouldn't enter this if statement.
+            disabled_defaults_string = str(self._disabled_settings_defaults[0]) # Must be at least 1 item, otherwise we wouldn't enter this if statement.
             for item in self._disabled_settings_defaults[1:]:
                 disabled_defaults_string += "," + str(item)
 
diff --git a/plugins/VersionUpgrade/VersionUpgrade21to22/VersionUpgrade21to22.py b/plugins/VersionUpgrade/VersionUpgrade21to22/VersionUpgrade21to22.py
index 0118a96aa8..076bd7cc5e 100644
--- a/plugins/VersionUpgrade/VersionUpgrade21to22/VersionUpgrade21to22.py
+++ b/plugins/VersionUpgrade/VersionUpgrade21to22/VersionUpgrade21to22.py
@@ -1,10 +1,10 @@
 # Copyright (c) 2016 Ultimaker B.V.
 # Cura is released under the terms of the AGPLv3 or higher.
 
-from UM.VersionUpgrade import VersionUpgrade #Superclass of the plugin.
+from UM.VersionUpgrade import VersionUpgrade # Superclass of the plugin.
 
-from . import MachineInstance #To upgrade machine instances.
-from . import Profile #To upgrade profiles.
+from . import MachineInstance # To upgrade machine instances.
+from . import Profile # To upgrade profiles.
 
 ##  Converts configuration from Cura 2.1's file formats to Cura 2.2's.
 #
@@ -28,7 +28,7 @@ class VersionUpgrade21to22(VersionUpgrade):
     #   not of the correct format.
     def upgradeProfile(self, serialised):
         profile = Profile.importVersion1(serialised)
-        if not profile: #Invalid file format.
+        if not profile: # Invalid file format.
             return None
         return profile.exportVersion2()
 
@@ -42,10 +42,10 @@ class VersionUpgrade21to22(VersionUpgrade):
     @staticmethod
     def translateSettings(settings):
         for key, value in settings.items():
-            if key == "speed_support_lines": #Setting key was changed for 2.2.
+            if key == "speed_support_lines": # Setting key was changed for 2.2.
                 del settings[key]
                 settings["speed_support_infill"] = value
-            if key == "retraction_combing": #Combing was made into an enum instead of a boolean.
+            if key == "retraction_combing": # Combing was made into an enum instead of a boolean.
                 settings[key] = "off" if (value == "False") else "all"
         return settings