René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Cannot use Qt4Agg backend in mpl 3.2.1","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\n**Bug summary**\r\nCan't use qt4agg, error reported below.\r\n\r\nDowngrade to matplotlib 3.1.3 solves the problem.\r\n\r\n\u003c!--A short 1-2 sentences that succinctly describes the bug--\u003e\r\n\r\n**Code for reproduction**\r\n\r\n\u003c!--A minimum code snippet required to reproduce the bug.\r\nPlease make sure to minimize the number of dependencies required, and provide\r\nany necessary plotted data.\r\nAvoid using threads, as Matplotlib is (explicitly) not thread-safe.--\u003e\r\n\r\n\r\n```python\r\nimport matplotlib as mpl\r\nmpl.use('qt4agg')\r\n```\r\nOr, set it to Qt4Agg in `matplotlibrc` file.\r\n\r\n**Actual outcome**\r\n\r\n\u003c!--The output produced by the above code, which may be a screenshot, console output, etc.--\u003e\r\n\r\n```\r\nImportError: cannot import name '_isdeleted' \r\nFailed to enable GUI event loop integration for 'qt5'\r\n```\r\n\r\n\r\n\u003c!--A description of the expected outcome from the code snippet--\u003e\r\n\u003c!--If this used to work in an earlier version of Matplotlib, please note the version it used to work on--\u003e\r\n\r\n**Matplotlib version**\r\n\u003c!--Please specify your platform and versions of the relevant libraries you are using:--\u003e\r\n  * Operating system: win 10 LTSC 2019\r\n  * Matplotlib version: 3.2.1\r\n  * Matplotlib backend (`print(matplotlib.get_backend())`): can only use TkAgg\r\n  * Python version: 3.6\r\n\r\n\u003c!--Please tell us how you installed matplotlib and python e.g., from source, pip, conda--\u003e\r\n\u003c!--If you installed from conda, please specify which channel you used if not the default--\u003e\r\n\r\n","author":{"url":"https://github.com/alexysong","@type":"Person","name":"alexysong"},"datePublished":"2020-06-09T02:08:43.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":1},"url":"https://github.com/17594/matplotlib/issues/17594"}