"""

        Revoke permission for users group on given repository

        :param repo: Instance of Repository, repository_id, or repository name

        :param group_name: Instance of UserGroup, users_group_id,

            or users group name

        """

        repo = self._get_repo(repo)

        group_name = self.__get_users_group(group_name)

        obj = self.sa.query(UsersGroupRepoToPerm)\

            .filter(UsersGroupRepoToPerm.repository == repo)\

            .filter(UsersGroupRepoToPerm.users_group == group_name)\

            .scalar()

        if obj:

            self.sa.delete(obj)

            log.debug('Revoked perm to %s on %s' % (repo, group_name))

    def delete_stats(self, repo_name):

        """

        removes stats for given repo

        :param repo_name:

        """

        try:

            obj = self.sa.query(Statistics)\

            self.sa.delete(obj)

        except:

            log.error(traceback.format_exc())

            raise

    def __create_repo(self, repo_name, alias, parent, clone_uri=False):

        """

        makes repository on filesystem. It's group aware means it'll create

        a repository within a group, and alter the paths accordingly of

        group location

        :param repo_name:

        :param alias:

        :param parent_id:

        :param clone_uri:

        """

        from rhodecode.lib.utils import is_valid_repo, is_valid_repos_group

        from rhodecode.model.scm import ScmModel

        if parent:

            new_parent_path = os.sep.join(parent.full_path_splitted)

        else:

            new_parent_path = ''