Fixed a bunch of error which were reported by PyCharm's code analysis.

cura/CuraApplication.py

@@ -20,6 +20,8 @@ from UM.JobQueue import JobQueue
 from UM.SaveFile import SaveFile
 from UM.Scene.Selection import Selection
 from UM.Scene.GroupDecorator import GroupDecorator
+from UM.Settings.ContainerStack import ContainerStack
+from UM.Settings.InstanceContainer import InstanceContainer
 from UM.Settings.Validator import Validator
 from UM.Message import Message
 from UM.i18n import i18nCatalog
@@ -148,11 +150,11 @@ class CuraApplication(QtApplication):
 
         UM.VersionUpgradeManager.VersionUpgradeManager.getInstance().setCurrentVersions(
             {
-                ("quality", UM.Settings.InstanceContainer.InstanceContainer.Version):    (self.ResourceTypes.QualityInstanceContainer, "application/x-uranium-instancecontainer"),
-                ("machine_stack", UM.Settings.ContainerStack.ContainerStack.Version): (self.ResourceTypes.MachineStack, "application/x-uranium-containerstack"),
-                ("extruder_train", UM.Settings.ContainerStack.ContainerStack.Version): (self.ResourceTypes.ExtruderStack, "application/x-uranium-extruderstack"),
+                ("quality", InstanceContainer.Version):    (self.ResourceTypes.QualityInstanceContainer, "application/x-uranium-instancecontainer"),
+                ("machine_stack", ContainerStack.Version): (self.ResourceTypes.MachineStack, "application/x-uranium-containerstack"),
+                ("extruder_train", ContainerStack.Version): (self.ResourceTypes.ExtruderStack, "application/x-uranium-extruderstack"),
                 ("preferences", Preferences.Version):               (Resources.Preferences, "application/x-uranium-preferences"),
-                ("user", UM.Settings.InstanceContainer.InstanceContainer.Version):       (self.ResourceTypes.UserInstanceContainer, "application/x-uranium-instancecontainer")
+                ("user", InstanceContainer.Version):       (self.ResourceTypes.UserInstanceContainer, "application/x-uranium-instancecontainer")
             }
         )
 

cura/Settings/MachineNameValidator.py

@@ -6,7 +6,7 @@ from PyQt5.QtGui import QValidator
 import os #For statvfs.
 import urllib #To escape machine names for how they're saved to file.
 
-import UM.Resources
+from UM.Resources import Resources
 from UM.Settings.ContainerRegistry import ContainerRegistry
 from UM.Settings.InstanceContainer import InstanceContainer
 
@@ -19,7 +19,7 @@ class MachineNameValidator(QObject):
 
         #Compute the validation regex for printer names. This is limited by the maximum file name length.
         try:
-            filename_max_length = os.statvfs(UM.Resources.getDataStoragePath()).f_namemax
+            filename_max_length = os.statvfs(Resources.getDataStoragePath()).f_namemax
         except AttributeError: #Doesn't support statvfs. Probably because it's not a Unix system.
             filename_max_length = 255 #Assume it's Windows on NTFS.
         machine_name_max_length = filename_max_length - len("_current_settings.") - len(ContainerRegistry.getMimeTypeForContainer(InstanceContainer).preferredSuffix)
@@ -41,7 +41,7 @@ class MachineNameValidator(QObject):
     def validate(self, name, position):
         #Check for file name length of the current settings container (which is the longest file we're saving with the name).
         try:
-            filename_max_length = os.statvfs(UM.Resources.getDataStoragePath()).f_namemax
+            filename_max_length = os.statvfs(Resources.getDataStoragePath()).f_namemax
         except AttributeError: #Doesn't support statvfs. Probably because it's not a Unix system.
             filename_max_length = 255 #Assume it's Windows on NTFS.
         escaped_name = urllib.parse.quote_plus(name)

cura/Settings/SettingOverrideDecorator.py

@@ -8,7 +8,7 @@ from UM.Signal import Signal, signalemitter
 from UM.Settings.ContainerStack import ContainerStack
 from UM.Settings.InstanceContainer import InstanceContainer
 from UM.Settings.ContainerRegistry import ContainerRegistry
-import UM.Logger
+from UM.Logger import Logger
 
 from UM.Application import Application
 
@@ -99,7 +99,7 @@ class SettingOverrideDecorator(SceneNodeDecorator):
                     Application.getInstance().getBackend().needsSlicing()
                     Application.getInstance().getBackend().tickle()
             else:
-                UM.Logger.log("e", "Extruder stack %s below per-object settings does not exist.", self._extruder_stack)
+                Logger.log("e", "Extruder stack %s below per-object settings does not exist.", self._extruder_stack)
         else:
             self._stack.setNextStack(Application.getInstance().getGlobalContainerStack())
 

plugins/CuraProfileReader/CuraProfileReader.py

@@ -2,7 +2,7 @@
 # Cura is released under the terms of the AGPLv3 or higher.
 import configparser
 
-from UM import PluginRegistry
+from UM.PluginRegistry import PluginRegistry
 from UM.Logger import Logger
 from UM.Settings.InstanceContainer import InstanceContainer  # The new profile to make.
 from cura.ProfileReader import ProfileReader

plugins/RemovableDriveOutputDevice/__init__.py

@@ -2,7 +2,7 @@
 # Cura is released under the terms of the AGPLv3 or higher.
 
 from UM.Platform import Platform
-
+from UM.Logger import Logger
 from UM.i18n import i18nCatalog
 catalog = i18nCatalog("cura")
 

plugins/VersionUpgrade/VersionUpgrade21to22/MachineInstance.py

@@ -3,7 +3,7 @@
 
 import UM.VersionUpgrade #To indicate that a file is of incorrect format.
 import UM.VersionUpgradeManager #To schedule more files to be upgraded.
-import UM.Resources #To get the config storage path.
+from UM.Resources import Resources #To get the config storage path.
 
 import configparser #To read config files.
 import io #To write config files to strings as if they were files.
@@ -107,7 +107,7 @@ class MachineInstance:
         user_profile["values"] = {}
 
         version_upgrade_manager = UM.VersionUpgradeManager.VersionUpgradeManager.getInstance()
-        user_storage = os.path.join(UM.Resources.getDataStoragePath(), next(iter(version_upgrade_manager.getStoragePaths("user"))))
+        user_storage = os.path.join(Resources.getDataStoragePath(), next(iter(version_upgrade_manager.getStoragePaths("user"))))
         user_profile_file = os.path.join(user_storage, urllib.parse.quote_plus(self._name) + "_current_settings.inst.cfg")
         if not os.path.exists(user_storage):
             os.makedirs(user_storage)

plugins/VersionUpgrade/VersionUpgrade21to22/Profile.py

@@ -3,6 +3,8 @@
 
 import configparser #To read config files.
 import io #To write config files to strings as if they were files.
+from typing import Dict
+from typing import List
 
 import UM.VersionUpgrade
 from UM.Logger import Logger