René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Notebook backend broken on Master","articleBody":"Just trying to do something simple like:\n\n``` python\n%matplotlib notebook\nimport matplotlib.pyplot as plt\nplt.plot(range(10))\nplt.tight_layout()\n```\n\nresults in \n\n```\nTraceback (most recent call last):\n  File \"/Users/jhn/Envs/matplotlibbisect/lib/python3.5/site-packages/ipykernel/comm/manager.py\", line 137, in comm_msg\n    comm.handle_msg(msg)\n  File \"/Users/jhn/Envs/matplotlibbisect/lib/python3.5/site-packages/ipykernel/comm/comm.py\", line 164, in handle_msg\n    self._msg_callback(msg)\n  File \"/Users/jhn/Envs/matplotlibbisect/lib/python3.5/site-packages/matplotlib/backends/backend_nbagg.py\", line 304, in on_message\n    self.manager.handle_json(message)\n  File \"/Users/jhn/Envs/matplotlibbisect/lib/python3.5/site-packages/matplotlib/backends/backend_webagg_core.py\", line 485, in handle_json\n    self.canvas.handle_event(content)\n  File \"/Users/jhn/Envs/matplotlibbisect/lib/python3.5/site-packages/matplotlib/backends/backend_webagg_core.py\", line 272, in handle_event\n    return handler(event)\n  File \"/Users/jhn/Envs/matplotlibbisect/lib/python3.5/site-packages/matplotlib/backends/backend_webagg_core.py\", line 288, in handle_draw\n    self.draw()\n  File \"/Users/jhn/Envs/matplotlibbisect/lib/python3.5/site-packages/matplotlib/backends/backend_webagg_core.py\", line 181, in draw\n    self.manager.refresh_all()\n  File \"/Users/jhn/Envs/matplotlibbisect/lib/python3.5/site-packages/matplotlib/backends/backend_webagg_core.py\", line 489, in refresh_all\n    diff = self.canvas.get_diff_image()\n  File \"/Users/jhn/Envs/matplotlibbisect/lib/python3.5/site-packages/matplotlib/backends/backend_webagg_core.py\", line 232, in get_diff_image\n    None, compression=6, filter=_png.PNG_FILTER_NONE)\nTypeError: Object does not appear to be a 8-bit string path or a Python file-like object\n```\n\ngit bisect tells me that it was broken by 9758da584590910c9b8f09285c9337107721de03\n","author":{"url":"https://github.com/jenshnielsen","@type":"Person","name":"jenshnielsen"},"datePublished":"2016-01-29T14:36:05.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":3},"url":"https://github.com/5944/matplotlib/issues/5944"}