def _split_optional_netmask(address):
    addr = str(address).split('/')
    if len(addr) > 2:
        raise AddressValueError("Only one '/' permitted in %r" % address)
    return addr
Helper to split the netmask and raise AddressValueError if needed
dataset/ETHPy150Open Exa-Networks/exabgp/lib/exabgp/dep/ipaddress.py/_split_optional_netmask