ModuleNotFoundError: No module named 'pycocotools._mask'

This error message indicates that the Python module `pycocotools._mask` is missing.

To resolve this issue, you can try reinstalling the `pycocotools` package using the following command:

pip install pycocotools --no-cache-dir

If the issue persists, you can try installing the package from its source code:

git clone https://github.com/cocodataset/cocoapi.git
cd cocoapi/PythonAPI
python setup.py install --user

Make sure to replace `python` with the correct version of Python you are using.