def _checkDataSample(self, data_sample):
        try:
            len(data_sample)
        except __HOLE__:
            raise ValueError("data_sample must be a sequence")

        if len(data_sample):
            self._checkRecordPairType(data_sample[0])

        else:
            warnings.warn("You submitted an empty data_sample")
dataset/ETHPy150Open datamade/dedupe/dedupe/api.py/ActiveMatching._checkDataSample