debugging elastic-recheck results in AttributeError: 'module' object has no attribute 'Cmd'

When trying to run elastic recheck in a debugger (pdb /pycharm) I get the following stack trace:

pydev debugger: process 12116 is connecting

Traceback (most recent call last):
  File "/home/stack/pycharm-community-5.0.1/helpers/pydev/pydevd.py", line 2403, in <module>
    globals = debugger.run(setup['file'], None, None, is_module)
  File "/home/stack/pycharm-community-5.0.1/helpers/pydev/pydevd.py", line 1794, in run
    launch(file, globals, locals) # execute the script
  File "/home/stack/pycharm-community-5.0.1/helpers/pycharm/utrunner.py", line 140, in <module>
    module = loadSource(a[0])
  File "/home/stack/pycharm-community-5.0.1/helpers/pycharm/utrunner.py", line 41, in loadSource
    module = imp.load_source(moduleName, fileName)
  File "/home/stack/elastic-recheck/elastic_recheck/tests/unit/test_stream.py", line 17, in <module>
    import fixtures
  File "/home/stack/venv/er/local/lib/python2.7/site-packages/fixtures/__init__.py", line 80, in <module>
    from fixtures.fixture import (
  File "/home/stack/venv/er/local/lib/python2.7/site-packages/fixtures/fixture.py", line 28, in <module>
    from testtools.compat import (
  File "/home/stack/venv/er/local/lib/python2.7/site-packages/testtools/__init__.py", line 59, in <module>
    from testtools.matchers._impl import (
  File "/home/stack/venv/er/local/lib/python2.7/site-packages/testtools/matchers/__init__.py", line 83, in <module>
    from ._doctest import (
  File "/home/stack/venv/er/local/lib/python2.7/site-packages/testtools/matchers/_doctest.py", line 7, in <module>
    import doctest
  File "/usr/lib/python2.7/doctest.py", line 99, in <module>
    import unittest, difflib, pdb, tempfile
  File "/usr/lib/python2.7/pdb.py", line 59, in <module>
    class Pdb(bdb.Bdb, cmd.Cmd):
AttributeError: 'module' object has no attribute 'Cmd'

Expected behavior: No AttributeError and debugger successfully loads