'Generate a sequence of scannable file suffixes in the
preferred order of scanning.'

def _gen_suffixes(self):

    (yield '.py')
    (yield '.pyw')
    if _SCAN_BINARY_FILES:
        (yield '.pyc')
        (yield '.pyo')
        for (suffix, mode, mod_type) in imp.get_suffixes():
            if ((suffix[0] == '.') and (mod_type == imp.C_EXTENSION)):
                (yield suffix)
