pylance: Address more type warnings.

renpy/display/layout.py

@@ -624,6 +624,9 @@ class MultiBox(Container):
     _camera_list = None # type: list|None
     layers = None # type: dict|None
 
+    # Used when this is representing a layer.
+    raw_child = None # type: renpy.display.core.Displayable|None
+    layer_name = None # type: str|None
 
     def __init__(self, spacing=None, layout=None, style='default', **properties):
 
@@ -2431,6 +2434,11 @@ class Layer(AdjustTimes):
         anything exceeding the bounds will be trimmed.
     """
 
+    # An instance variable that's used to store the layer_transitions
+    # when this layer s being processed. (This is only being created
+    # as a dict for typing purposes.)
+    layers = { }
+
     def __init__(self, layer, **properties):
         self.layer = layer
         self._clipping = properties.pop('clipping', True)

renpy/display/movetransition.py

@@ -529,11 +529,11 @@ def MoveTransition(delay, old_widget=None, new_widget=None, enter=None, leave=No
 
         # If we're dealing with a wrapped layer widget, merge the raw
         # children then re-apply the transform.
-        if hasattr(new, 'raw_child'):
+        if getattr(new, 'raw_child', None):
             rv = new
 
             new = new.raw_child
-            layer = new.layer_name
+            layer = new.layer_name # type: ignore
 
             if (isinstance(new, renpy.display.layout.MultiBox) and
                 layer in layers and new.scene_list is not None):