'Delete the named folder, which must be empty.'

def remove_folder(self, folder):

    path = os.path.join(self._path, folder)
    entries = os.listdir(path)
    if (entries == ['.mh_sequences']):
        os.remove(os.path.join(path, '.mh_sequences'))
    elif (entries == []):
        pass
    else:
        raise NotEmptyError(('Folder    not    empty:    %s' % self._path))
    os.rmdir(path)
