def b1_mapping(char):
    if stringprep.in_table_b1(char):
        return ""
    else:
        return None
Do RFC 3454 B.1 table mapping.
dataset/ETHPy150Open kuri65536/python-for-android/python3-alpha/python-libs/pyxmpp2/xmppstringprep.py/b1_mapping