def __or__(self, other ):
        """Implementation of | operator - returns C{L{MatchFirst}}"""
        if isinstance( other, basestring ):
            other = ParserElement.literalStringClass( other )
        if not isinstance( other, ParserElement ):
            warnings.warn(type(other) % "Cannot combine element of type %s with ParserElement",
                    SyntaxWarning, stacklevel=2)
            return None
        return MatchFirst( [ self, other ] )
dataset/ETHPy150Open Exa-Networks/exabgp/lib/exabgp/dep/pyparsing.py/ParserElement.__or__/swapped operands of `%`