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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"`fontset` from `mathtext` throwing error after setting Text `font=`","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\nThis issue was initially reported by the user  @ain-soph at the PR #18145. I was able to reproduce the error with the provided code and decided to formalize the issue here while I work on it.\r\n\r\nCode for reproduction:\r\n```python\r\nimport matplotlib.pyplot as plt\r\nimport matplotlib\r\n\r\nplt.figure(figsize=(6, 5))\r\nplt.plot(range(11), color=\"0.9\")\r\nmsg = (r\"Normal Text. $Text\\ in\\ math\\ mode:\\ \"\r\n       r\"\\int_{0}^{\\infty } x^2 dx$\")\r\nplt.text(1, 7, msg, size=12, font='Arial')  # math_fontfamily='cm'\r\nplt.show()\r\n```\r\n\r\n\r\nAnd the outcome is:\r\n```\r\n....\r\n File \"c:\\repos\\matplotlib\\matplotlib\\lib\\matplotlib\\mathtext.py\", line 431, in _parse_cached\r\n    else _api.check_getitem(\r\n  File \"c:\\repos\\matplotlib\\matplotlib\\lib\\matplotlib\\_api\\__init__.py\", line 187, in check_getitem\r\n    raise ValueError(\r\nValueError: None is not a valid value for fontset; supported values are 'cm', 'dejavuserif', 'dejavusans', 'stix', 'stixsans', 'custom'\r\n```\r\n\r\n**Matplotlib version**: 3.4.1.post563+g679ca172e.d20210428\r\n","author":{"url":"https://github.com/diegopetrola","@type":"Person","name":"diegopetrola"},"datePublished":"2021-04-28T17:46:06.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":10},"url":"https://github.com/20099/matplotlib/issues/20099"}