def prep_for_dist(self, finder, build_isolation):
        # type: (PackageFinder, bool) -> Any
        """Ensure that we can get a Dist for this requirement."""
        raise NotImplementedError
Ensure that we can get a Dist for this requirement.
stackoverflow/venv/lib/python3.6/site-packages/pip-19.0.3-py3.6.egg/pip/_internal/operations/prepare.py