python version

What python version is this module targeting?

There are no f-strings in use here, which would point to a python version before [3.6](https://docs.python.org/3.6/whatsnew/3.6.html#pep-498-formatted-string-literals).
Also, there are type hints, but only in comments, which would indicate a python version before [3.5](https://docs.python.org/3.5/whatsnew/3.5.html)

No file or test is named. Start by locating the repository's Python-version metadata and the module source, then compare the supported version with the syntax noted in the issue. Done means the target Python version is clearly established and documented or the question receives a definitive answer.

Written by the indexing model from the issue text.