WARNING: .../examples/coordinates/plot_obs-planning.py failed to execute correctly: Traceback (most recent call last):  File ".../sphinx_gallery/scrapers.py", line 333, in save_figures    rst = scraper(block, block_vars, gallery_conf)  File ".../sphinx_gallery/scrapers.py", line 149, in matplotlib_scraper    fig.savefig(image_path, **these_kwargs)  File ".../matplotlib/figure.py", line 2959, in savefig    self.canvas.print_figure(fname, **kwargs)  File ".../matplotlib/backend_bases.py", line 2255, in print_figure    result = print_method(  File ".../matplotlib/backend_bases.py", line 1669, in wrapper    return func(*args, **kwargs)  File ".../matplotlib/backends/backend_agg.py", line 508, in print_png    FigureCanvasAgg.draw(self)  File ".../matplotlib/backends/backend_agg.py", line 406, in draw    self.figure.draw(self.renderer)  File ".../matplotlib/artist.py", line 74, in draw_wrapper    result = draw(artist, renderer, *args, **kwargs)  File ".../matplotlib/artist.py", line 51, in draw_wrapper    return draw(artist, renderer, *args, **kwargs)  File ".../matplotlib/figure.py", line 2734, in draw    mimage._draw_list_compositing_images(  File ".../matplotlib/image.py", line 132, in _draw_list_compositing_images    a.draw(renderer)  File ".../matplotlib/artist.py", line 51, in draw_wrapper    return draw(artist, renderer, *args, **kwargs)  File ".../matplotlib/_api/deprecation.py", line 431, in wrapper    return func(*inner_args, **inner_kwargs)  File ".../matplotlib/axes/_base.py", line 2925, in draw    mimage._draw_list_compositing_images(renderer, self, artists)  File ".../matplotlib/image.py", line 132, in _draw_list_compositing_images    a.draw(renderer)  File ".../matplotlib/artist.py", line 51, in draw_wrapper    return draw(artist, renderer, *args, **kwargs)  File ".../matplotlib/legend.py", line 614, in draw    self._legend_box.draw(renderer)  File ".../matplotlib/offsetbox.py", line 368, in draw    c.draw(renderer)  File ".../matplotlib/offsetbox.py", line 368, in draw    c.draw(renderer)  File ".../matplotlib/offsetbox.py", line 368, in draw    c.draw(renderer)  [Previous line repeated 1 more time]  File ".../matplotlib/offsetbox.py", line 694, in draw    c.draw(renderer)  File ".../matplotlib/artist.py", line 51, in draw_wrapper    return draw(artist, renderer, *args, **kwargs)  File ".../matplotlib/collections.py", line 1009, in draw    super().draw(renderer)  File ".../matplotlib/artist.py", line 51, in draw_wrapper    return draw(artist, renderer, *args, **kwargs)  File ".../matplotlib/collections.py", line 380, in draw    len(facecolors) == 1 and len(edgecolors) == 1 andTypeError: object of type 'NoneType' has no len()