def _getter(self, key, raiseerr=True):
        if key in self._keymap:
            processor, obj, index = self._keymap[key]
        else:
            ret = self._key_fallback(key, raiseerr)
            if ret is None:
                return None
            processor, obj, index = ret

        if index is None:
            raise exc.InvalidRequestError(
                "Ambiguous column name '%s' in "
                "result set column descriptions" % obj)

        return operator.itemgetter(index)
dataset/ETHPy150Open zzzeek/sqlalchemy/lib/sqlalchemy/engine/result.py/ResultMetaData._getter/original