sudo pip3 install main_package/
sudo pip3 install some_plugin/
python3 -c "import mainpackage; print(mainpackage.a)"
# -> hello
python3 -c "import mainpackage.ext.someplugin; print(mainpackage.ext.someplugin.a)"
# -> plugin
sudo pip3 install -e main_package/
sudo pip3 install -e some_plugin/
python3 -c "import mainpackage; print(mainpackage.a)"
# -> hello
python3 -c "import mainpackage.ext.someplugin; print(mainpackage.ext.someplugin.a)"
# -> ERROR
# Traceback (most recent call last):
# File "<string>", line 1, in <module>
# ModuleNotFoundError: No module named 'mainpackage.ext.someplugin'