Library reference is a GPL library, but this library is not GPL-licenced

[chrisjrn]

The Python unidecode library (https://pypi.python.org/pypi/Unidecode) which is listed as the reference for this library is released under the GPL version 2, which requires derivatives to also be released under GPL version 2 or later.

[RESDXChgfore9hing]

its probably too late but i think you isunderstand the legal definition.
It is a conceptual derivative:idea,but not code itself.
So they have full right to put it in any license they want.
Those license generally license the codes and resources. not the mindset nor process.
eg,xxx has tiktok,concept short video. x year later,youtube has youtube shorts.
and there are thousands more example if you pay attention to the large business with international scale.

The idea as you can see is copied.but not code itself.