@staticmethod
def real_files_in_zf(zf):
    """Return a list of internal paths of real files in a zip file, based on the 'external_attr' values"""
    from os.path import basename
    for e in zf.infolist():
        if basename(e.filename).startswith('__') or basename(e.filename
            ).startswith('.'):
            continue
        if bool(e.external_attr >> 31 & 1 or e.external_attr == 0 or e.
            external_attr == 32 or e.external_attr == 128):
            yield e.filename
