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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"RcParams is fundamentally broken","articleBody":"\u003c!--To help us understand and resolve your issue, please fill out the form to the best of your ability.--\u003e\r\n\u003c!--You can feel free to delete the sections that do not apply.--\u003e\r\n\r\n### Bug report\r\n\r\nAnyone tried:\r\n\r\n~~~\r\n\u003e\u003e\u003e import matplotlib\r\n\u003e\u003e\u003e len(matplotlib.rcParams)\r\n0\r\n~~~\r\n\r\nA great example of shooting yourself in the foot with multiple inheritance. Essentially, we do\r\n\r\n~~~\r\nclass RcParams(MutableMapping, dict):\r\n    def __getitem__(self, key):\r\n        return dict.__getitem__(self, key)\r\n\r\n    def __setitem__(self, key, val):\r\n        return dict.__setitem__(self, key, val)\r\n~~~\r\n\r\nbut do not reimplement `__len__`. You can work out the consequences yourself.\r\n\r\n### Proposed solution\r\n\r\nDo not inherit `RcParams` from dict, and use a private data dict instead.","author":{"url":"https://github.com/timhoffm","@type":"Person","name":"timhoffm"},"datePublished":"2018-10-20T21:37:20.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":7},"url":"https://github.com/12576/matplotlib/issues/12576"}