import unittest

suite = unittest.TestLoader().discover("./tests")
runner = unittest.TextTestRunner()

for build in [build1, build2]:
    get_the_build(build)
    runner.run(suite)

Traceback (most recent call last):
  File "D:/Path/to/my/folder/run_tests.py", line 9, in <module>
    runner.run(suite)
  File "C:Program Files (x86)Python36-32libunittestrunner.py", line 176, in run
    test(result)
  File "C:Program Files (x86)Python36-32libunittestsuite.py", line 84, in __call__
    return self.run(*args, **kwds)
  File "C:Program Files (x86)Python36-32libunittestsuite.py", line 122, in run
    test(result)
TypeError: 'NoneType' object is not callable