sphinx autodoc_mock_import type errors

Question

I'm attempting to document my code with sphinx autodoc but have run into problems with properties imported from external projects.

For example, this python script:

import myexternal

var = 5.0 * myexternal.constant
print(var)

imports an external package and attempts to use an internally defined constant. To account for the package in autodoc I added this line to my sphinx conf file:

autodoc_mock_imports = ['myexternal']

When I build sphinx I get a TypeError:

TypeError: unsupported operand type(s) for *: 'float' and 'constant'

Is there a way to setup the conf file to define 'constant' as type float? or ignore TypeErrors related to mocked packages?