set env var MPLCONFIGDIR
```
WARNING (MainThread) [matplotlib] Matplotlib created a temporary config/cache directory at /tmp/matplotlib-[...] because the default path (/home/hass/.config/matplotlib) is not a writable directory; it is highly recommended to set the MPLCONFIGDIR environment variable to a writable directory, in particular to speed up the import of Matplotlib and to better support multiprocessing.
```