tox tests fail

[dermatologist]

There is a (temporary) issue because of Tensorflows dependency on numpy fixed to < 1.20
To prevent errors, install numpy with pip install numpy==1.20.1. Ignore the warnings about incompatibility with TF.
This extra step has to be added to tox.ini. as install_command ?

[dermatologist]

Error in 3.8.1

ERROR: Cannot install wheel==0.36.2 and wheel==0.37.0 because these package versions have conflicting dependencies.

ERROR: ResolutionImpossible: for help visit https://pip.pypa.io/en/latest/user_guide/#fixing-conflicting-dependencies
The conflict is caused by:
    The user requested wheel==0.37.0
    The user requested wheel==0.36.2

To fix this you could try to:
1. loosen the range of package versions you've specified
2. remove package versions to allow pip attempt to solve the dependency conflict