Matplotlib exception while official examples run

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NotImplementedError                       Traceback (most recent call last)
<ipython-input-3-0842c2f8d975> in <module>
----> 1 s0.draw_poincare(filename='poincare1.png')
      2 plt.legend();

c:\opt\miniconda3\lib\site-packages\py_pol\stokes.py in draw_poincare(self, angle_view, label, filename)
    617             kind='scatter',
    618             color='r',
--> 619             label=label)
    620 
    621         if filename not in ['', None]:

c:\opt\miniconda3\lib\site-packages\py_pol\drawings.py in draw_poincare_sphere(stokes_points, angle_view, is_normalized, kind, color, label, filename)
     75     fig = plt.figure()
     76     ax = fig.add_subplot(111, projection='3d')
---> 77     ax.set_aspect('equal')
     78 
     79     u = linspace(0, 360 * degrees, 90)

c:\opt\miniconda3\lib\site-packages\matplotlib\axes\_base.py in set_aspect(self, aspect, adjustable, anchor, share)
   1279         if (not cbook._str_equal(aspect, 'auto')) and self.name == '3d':
   1280             raise NotImplementedError(
-> 1281                 'It is not currently possible to manually set the aspect '
   1282                 'on 3D axes')
   1283 

NotImplementedError: It is not currently possible to manually set the aspect on 3D axes