code: async def queryone(self, stmt, *args):
          
          results = await self.query(stmt, *args)
          if len(results) == 0:
              raise NoResultError()
          elif len(results) > 1:
              raise ValueError("Expected 1 result, got %d" % len(results))
          return results[0]
docs: Query for exactly one result.
  
          Raises NoResultError if there are no results, or ValueError if
          there are more than one.