Remove a distribution from the finder. This will update internal
        information about who provides what.
        :param dist: The distribution to remove.

def remove_distribution(self, dist):
        """
        Remove a distribution from the finder. This will update internal
        information about who provides what.
        :param dist: The distribution to remove.
        """
        logger.debug('removing distribution %s', dist)
        name = dist.key
        del self.dists_by_name[name]
        del self.dists[(name, dist.version)]
        for p in dist.provides:
            name, version = parse_name_and_version(p)
            logger.debug('Remove from provided: %s, %s, %s', name, version, dist)
            s = self.provided[name]
            s.remove((version, dist))
            if not s:
                del self.provided[name]