TYP: Fix return types of Gcf getters

Some return None when there is no figure available.

Author: QuLogic

lib/matplotlib/_pylab_helpers.pyi

@@ -6,7 +6,7 @@ from matplotlib.figure import Figure
 class Gcf:
     figs: OrderedDict[int, FigureManagerBase]
     @classmethod
-    def get_fig_manager(cls, num: int) -> FigureManagerBase: ...
+    def get_fig_manager(cls, num: int) -> FigureManagerBase | None: ...
     @classmethod
     def destroy(cls, num: int | FigureManagerBase) -> None: ...
     @classmethod
@@ -20,7 +20,9 @@ class Gcf:
     @classmethod
     def get_num_fig_managers(cls) -> int: ...
     @classmethod
-    def get_active(cls) -> FigureManagerBase: ...
+    def get_active(cls) -> FigureManagerBase | None: ...
+    @classmethod
+    def _set_new_active_manager(cls, manager: FigureManagerBase) -> None: ...
     @classmethod
     def set_active(cls, manager: FigureManagerBase) -> None: ...
     @classmethod

lib/matplotlib/pyplot.py

@@ -938,7 +938,7 @@ def figure(
 
         for hookspecs in rcParams["figure.hooks"]:
             module_name, dotted_name = hookspecs.split(":")
-            obj = importlib.import_module(module_name)
+            obj: Any = importlib.import_module(module_name)
             for part in dotted_name.split("."):
                 obj = getattr(obj, part)
             obj(fig)