导入 yt 停止工作并给出错误 - 如何修复它？

如何解决导入 yt 停止工作并给出错误 - 如何修复它？

请问导入yt后出现以下错误怎么办？几个月前它起作用了。我已经更新了 pip 并重新安装了它，但是错误仍然存​​在。

python3
Python 3.6.9 (default,Oct  8 2020,12:12:24) 
[GCC 8.4.0] on linux
Type "help","copyright","credits" or "license" for more information.
>>> import yt
/usr/lib/python3.6/_collections_abc.py:666: MatplotlibDeprecationWarning: The global colormaps dictionary is no longer considered public API.
  self[key]
Traceback (most recent call last):
  File "<stdin>",line 1,in <module>
  File "/home/linux/.local/lib/python3.6/site-packages/yt/__init__.py",line 76,in <module>
    from yt.data_objects.api import \
  File "/home/linux/.local/lib/python3.6/site-packages/yt/data_objects/api.py",line 16,in <module>
    from .grid_patch import \
  File "/home/linux/.local/lib/python3.6/site-packages/yt/data_objects/grid_patch.py",line 22,in <module>
    from yt.data_objects.data_containers import \
  File "/home/linux/.local/lib/python3.6/site-packages/yt/data_objects/data_containers.py",line 56,in <module>
    from yt.utilities.parallel_tools.parallel_analysis_interface import \
  File "/home/linux/.local/lib/python3.6/site-packages/yt/utilities/parallel_tools/parallel_analysis_interface.py",line 30,in <module>
    from yt.data_objects.image_array import ImageArray
  File "/home/linux/.local/lib/python3.6/site-packages/yt/data_objects/image_array.py",line 18,in <module>
    from yt.visualization.image_writer import write_bitmap,write_image
  File "/home/linux/.local/lib/python3.6/site-packages/yt/visualization/image_writer.py",line 29,in <module>
    import yt.utilities.png_writer as pw
  File "/home/linux/.local/lib/python3.6/site-packages/yt/utilities/png_writer.py",line 13,in <module>
    import matplotlib._png as _png
ModuleNotFoundError: No module named 'matplotlib._png'