My goal is to make a contribution to an open source Python project hosted on GitHub, which has an Apache 2.0 license. To do so, I wrote a few lines of code. However for a specific feature of my contribution, I called a python module installed through pypi, which has a LGPL-3 license.
When I asked the author of the Apache 2.0 licensed library about the possible incompatibility of the two licenses he told me:
If you just point to the the optional LGPL library in setup.py file I believe it's fine. You don't even have to change the license here. It is separate code. This library is even an optional part (kind of language-support plugin) and even GPL is allowed to license code separately in the case of plugins.
This setup.py mentioned above has an extras section where optional libraries will be installed (linked?) if the user specifies them during install.
Is this contribution possible at all, without any repercussions?
Should I include a license notice to the sub-directory where this LGPL-3 module is called (if included during setup)?