Do not do (in)equality tests with None. Use 'is' and 'is not' instead.

Author: WeatherGod

lib/mpl_toolkits/mplot3d/art3d.py

@@ -42,7 +42,7 @@ def get_dir_vector(zdir):
         return np.array((0, 1, 0))
     elif zdir == 'z':
         return np.array((0, 0, 1))
-    elif zdir == None:
+    elif zdir is None:
         return np.array((0, 0, 0))
     elif iterable(zdir) and len(zdir) == 3:
         return zdir

lib/mpl_toolkits/mplot3d/axes3d.py

@@ -366,7 +366,7 @@ def mouse_init(self, rotate_btn=1, zoom_btn=3):
         """
         self.button_pressed = None
         canv = self.figure.canvas
-        if canv != None:
+        if canv is not None:
             c1 = canv.mpl_connect('motion_notify_event', self._on_move)
             c2 = canv.mpl_connect('button_press_event', self._button_press)
             c3 = canv.mpl_connect('button_release_event', self._button_release)
@@ -492,7 +492,7 @@ def _on_move(self, event):
 
         x, y = event.xdata, event.ydata
         # In case the mouse is out of bounds.
-        if x == None:
+        if x is None:
             return
 
         dx, dy = x - self.sx, y - self.sy