when running
pypi-private -v publish <package name> <package version>
the below error appears:
from markupsafe import Markup, escape, soft_unicode
ImportError: cannot import name 'soft_unicode' from 'markupsafe'
It other words, markupsafe version 2.1.1 seems incompatible.
Workaround:
python -m pip uninstall markupsafe
python -m pip install markupsafe==2.0.1
Conclusion: it seems the version defined for markupsafe needs to be set properly.