Clean up more code

This fixes some typing and moves a property to protected, as it should be

cura/Machines/ContainerNode.py

@@ -9,9 +9,6 @@ from UM.ConfigurationErrorMessage import ConfigurationErrorMessage
 from UM.Logger import Logger
 from UM.Settings.InstanceContainer import InstanceContainer
 
-if TYPE_CHECKING:
-    from cura.Machines.QualityGroup import QualityGroup
-
 
 ##
 # A metadata / container combination. Use getContainer() to get the container corresponding to the metadata.
@@ -24,11 +21,11 @@ if TYPE_CHECKING:
 #     This is used in Variant, Material, and Quality Managers.
 #
 class ContainerNode:
-    __slots__ = ("_metadata", "container", "children_map")
+    __slots__ = ("_metadata", "_container", "children_map")
 
     def __init__(self, metadata: Optional[Dict[str, Any]] = None) -> None:
         self._metadata = metadata
-        self.container = None
+        self._container = None # type: Optional[InstanceContainer]
         self.children_map = OrderedDict()  # type: ignore  # This is because it's children are supposed to override it.
 
     ##  Get an entry value from the metadata
@@ -50,7 +47,7 @@ class ContainerNode:
             Logger.log("e", "Cannot get container for a ContainerNode without metadata.")
             return None
 
-        if self.container is None:
+        if self._container is None:
             container_id = self._metadata["id"]
             from UM.Settings.ContainerRegistry import ContainerRegistry
             container_list = ContainerRegistry.getInstance().findInstanceContainers(id = container_id)
@@ -59,9 +56,9 @@ class ContainerNode:
                 error_message = ConfigurationErrorMessage.getInstance()
                 error_message.addFaultyContainers(container_id)
                 return None
-            self.container = container_list[0]
+            self._container = container_list[0]
 
-        return self.container
+        return self._container
 
     def __str__(self) -> str:
         return "%s[%s]" % (self.__class__.__name__, self.getMetaDataEntry("id"))

cura/Machines/MaterialManager.py

@@ -21,7 +21,6 @@ from .VariantType import VariantType
 
 if TYPE_CHECKING:
     from UM.Settings.DefinitionContainer import DefinitionContainer
-    from UM.Settings.InstanceContainer import InstanceContainer
     from cura.Settings.GlobalStack import GlobalStack
     from cura.Settings.ExtruderStack import ExtruderStack
 

cura/Machines/Models/SettingVisibilityPresetsModel.py

@@ -58,7 +58,7 @@ class SettingVisibilityPresetsModel(ListModel):
                 break
         return result
 
-    def _populate(self):
+    def _populate(self) -> None:
         from cura.CuraApplication import CuraApplication
         items = []
         for file_path in Resources.getAllResourcesOfType(CuraApplication.ResourceTypes.SettingVisibilityPreset):
@@ -147,7 +147,7 @@ class SettingVisibilityPresetsModel(ListModel):
     def activePreset(self) -> str:
         return self._active_preset_item["id"]
 
-    def _onPreferencesChanged(self, name: str):
+    def _onPreferencesChanged(self, name: str) -> None:
         if name != "general/visible_settings":
             return
 

cura/Machines/QualityChangesGroup.py

@@ -24,9 +24,9 @@ class QualityChangesGroup(QualityGroup):
             ConfigurationErrorMessage.getInstance().addFaultyContainers(node.getMetaDataEntry("id"))
             return
 
-        if extruder_position is None: #Then we're a global quality changes profile.
+        if extruder_position is None:  # Then we're a global quality changes profile.
             self.node_for_global = node
-        else: #This is an extruder's quality changes profile.
+        else:  # This is an extruder's quality changes profile.
             self.nodes_for_extruders[extruder_position] = node
 
     def __str__(self) -> str:

cura/Machines/QualityNode.py

@@ -1,7 +1,7 @@
 # Copyright (c) 2018 Ultimaker B.V.
 # Cura is released under the terms of the LGPLv3 or higher.
 
-from typing import Optional, Dict, cast
+from typing import Optional, Dict, cast, Any
 
 from .ContainerNode import ContainerNode
 from .QualityChangesGroup import QualityChangesGroup
@@ -12,21 +12,21 @@ from .QualityChangesGroup import QualityChangesGroup
 #
 class QualityNode(ContainerNode):
 
-    def __init__(self, metadata: Optional[dict] = None) -> None:
+    def __init__(self, metadata: Optional[Dict[str, Any]] = None) -> None:
         super().__init__(metadata = metadata)
         self.quality_type_map = {}  # type: Dict[str, QualityNode] # quality_type -> QualityNode for InstanceContainer
 
     def getChildNode(self, child_key: str) -> Optional["QualityNode"]:
         return self.children_map.get(child_key)
 
-    def addQualityMetadata(self, quality_type: str, metadata: dict):
+    def addQualityMetadata(self, quality_type: str, metadata: Dict[str, Any]):
         if quality_type not in self.quality_type_map:
             self.quality_type_map[quality_type] = QualityNode(metadata)
 
     def getQualityNode(self, quality_type: str) -> Optional["QualityNode"]:
         return self.quality_type_map.get(quality_type)
 
-    def addQualityChangesMetadata(self, quality_type: str, metadata: dict):
+    def addQualityChangesMetadata(self, quality_type: str, metadata: Dict[str, Any]):
         if quality_type not in self.quality_type_map:
             self.quality_type_map[quality_type] = QualityNode()
         quality_type_node = self.quality_type_map[quality_type]