box% python
Python 3.8.6 (default, Sep 30 2020, 04:00:38)
[GCC 10.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from cmath import *
>>> log((1 + 4.2j)/(1 - 4.2j)) / 2j
(1.3370531459259951+2.7755575615628914e-17j)
>>> atan(4.2)
(1.3370531459259951+0j)
>>>