def single(self):
        records = list(self)
        num_records = len(records)
        if num_records == 0:
            raise ResultError("Cannot retrieve a single record, because this result is empty.")
        elif num_records != 1:
            raise ResultError("Expected a result with a single record, but this result contains at least one more.")
        else:
            return records[0]
Return the next record, failing if none or more than one remain.
dataset/ETHPy150Open nigelsmall/py2neo/py2neo/packages/neo4j/v1/session.py/StatementResult.single