Removed unused imports

cura/Settings/ExtruderStack.py

@@ -3,14 +3,10 @@
 
 from typing import Any, TYPE_CHECKING, Optional
 
-from PyQt5.QtCore import pyqtProperty, pyqtSignal, pyqtSlot
-
 from UM.Decorators import override
 from UM.MimeTypeDatabase import MimeType, MimeTypeDatabase
-from UM.Settings.ContainerStack import ContainerStack, InvalidContainerStackError
+from UM.Settings.ContainerStack import ContainerStack
 from UM.Settings.ContainerRegistry import ContainerRegistry
-from UM.Settings.InstanceContainer import InstanceContainer
-from UM.Settings.DefinitionContainer import DefinitionContainer
 from UM.Settings.Interfaces import ContainerInterface
 
 from . import Exceptions