error setting certificate verify locations

[AllenDowney]

I ran

pip install bitly_api

then I downloaded

https://github.com/bitly/bitly-api-python/blob/master/test/test_bitly_api.py

I set the environment variable BITLY_ACCESS_TOKEN to my access token and then ran

nosetests

All tests fail and report

BitlyError: (77, 'error setting certificate verify locations:\n  CAfile: /etc/pki/tls/certs/ca-bundle.crt\n  CApath: none')

I assume the problem is related to OAuth, but I don't know how to fix it. Thanks for any help.