def is_ancestor(self, ancestor_rev, rev):
        """Check if a commit  is an ancestor of another

        :param ancestor_rev: Rev which should be an ancestor
        :param rev: Rev to test against ancestor_rev
        :return: ``True``, ancestor_rev is an accestor to rev.
        """
        try:
            self.git.merge_base(ancestor_rev, rev, is_ancestor=True)
        except GitCommandError as err:
            if err.status == 1:
                return False
            raise
        return True
Check if a commit  is an ancestor of another

        :param ancestor_rev: Rev which should be an ancestor
        :param rev: Rev to test against ancestor_rev
        :return: ``True``, ancestor_rev is an accestor to rev.