The documentation for the cmath module is misleading on the behaviour near branch cuts. For example, the documentation for cmath.acos says: Return the arc cosine of x. There are two branch cuts: One ...

asottile commented on Aug 6, 2018 There were no changes to the cmath module between 3.6 and 3.7 -- perplexing. Also the build succeeded on i386 -- maybe it was a flake? I'm going to try re-uploading ...