def _get_all_po_filenames(locale_root, lang, po_files_path):
    """
    Get all po filenames from locale folder and return list of them.
    Assumes a directory structure:
    <locale_root>/<lang>/<po_files_path>/<filename>.
    """
    all_files = os.listdir(os.path.join(locale_root, lang, po_files_path))
    return filter(lambda s: s.endswith('.po'), all_files)
Get all po filenames from locale folder and return list of them.
    Assumes a directory structure:
    <locale_root>/<lang>/<po_files_path>/<filename>.