if new_parent_id:

            paths = RepoGroup.get(new_parent_id)\

                .full_path.split(RepoGroup.url_sep())

            new_parent_path = os.sep.join(paths)

        else:

            new_parent_path = ''

        # we need to make it str for mercurial

        repo_path = os.path.join(*map(lambda x: safe_str(x),

                                [self.repos_path, new_parent_path, repo_name]))

        # check if this path is not a repository

        if is_valid_repo(repo_path, self.repos_path):

            raise Exception('This path %s is a valid repository' % repo_path)

        # check if this path is a group

        if is_valid_repos_group(repo_path, self.repos_path):

            raise Exception('This path %s is a valid group' % repo_path)

        log.info('creating repo %s in %s @ %s' % (

                     repo_name, safe_unicode(repo_path), clone_uri

                )

        )

        backend = get_backend(alias)

        backend(repo_path, create=True, src_url=clone_uri)

    def __rename_repo(self, old, new):

        """

        renames repository on filesystem

        :param old: old name

        :param new: new name

        """

        log.info('renaming repo from %s to %s' % (old, new))

        old_path = os.path.join(self.repos_path, old)

        new_path = os.path.join(self.repos_path, new)

        if os.path.isdir(new_path):

            raise Exception(

                'Was trying to rename to already existing dir %s' % new_path

            )

        shutil.move(old_path, new_path)

    def __delete_repo(self, repo):

        """

        removes repo from filesystem, the removal is acctually made by

        added rm__ prefix into dir, and rename internat .hg/.git dirs so this

        repository is no longer valid for rhodecode, can be undeleted later on

        by reverting the renames on this repository