def _urn_to_port(urn):

    m = external_port_re.search(urn)
    if not m:
        raise BadURNError(urn)
    
    return (m.group('dpid'), int(m.group('port')))
Is this expression an atom (as opposed to a lambda expression applied
dataset/ETHPy150Open fp7-ofelia/ocf/expedient/src/python/plugins/openflow/plugin/gapi/rspec.py/_urn_to_port--crossover with--dataset/ETHPy150Open nltk/nltk/nltk/sem/logic.py/ApplicationExpression.is_atom