Hi Oppia Devs,
Just wanted to share a fix for an issue I faced recently in case any one else is running into the same error.
If you see the error "ModuleNotFoundError: No module named _bz2":
1. Install bz2 headers. Use the command "sudo apt-get install libbz2-dev" on Ubuntu.
2. Install Python 3 again so that the bz2 library gets included in "~/.pyenv/versions/3.7.10/lib/python3.7/". Use the command "pyenv install 3.7.10".