def parseImpl( self, instring, loc, doActions=True ):
        maxExcLoc = -1
        maxException = None
        for e in self.exprs:
            try:
                ret = e._parse( instring, loc, doActions )
                return ret
            except ParseException as err:
                if err.loc > maxExcLoc:
                    maxException = err
                    maxExcLoc = err.loc
            except __HOLE__:
                if len(instring) > maxExcLoc:
                    maxException = ParseException(instring,len(instring),e.errmsg,self)
                    maxExcLoc = len(instring)

        # only got here if no expression matched, raise exception for match that made it the furthest
        else:
            if maxException is not None:
                maxException.msg = self.errmsg
                raise maxException
            else:
                raise ParseException(instring, loc, "no defined alternatives to match", self)
dataset/ETHPy150Open pypa/pip/pip/_vendor/pyparsing.py/MatchFirst.parseImpl