Way to debug/fix errors with python ports such as these [py-paragrep]

[Jeffrey Bouquet]

Traceback (most recent call last):
  File "/usr/local/bin/paragrep", line 5, in <module>
    from pkg_resources import load_entry_point
  File "/usr/local/lib/python2.7/site-packages/pkg_resources.py", line 2837, in <module>
    working_set = WorkingSet._build_master()
  File "/usr/local/lib/python2.7/site-packages/pkg_resources.py", line 449, in _build_master
    ws.require(__requires__)
  File "/usr/local/lib/python2.7/site-packages/pkg_resources.py", line 742, in require
    needed = self.resolve(parse_requirements(requirements))
  File "/usr/local/lib/python2.7/site-packages/pkg_resources.py", line 639, in resolve
    raise DistributionNotFound(req)
pkg_resources.DistributionNotFound: grizzled-python>=1.0

Methodology or wrapper program or clue as to what to reinstall ???