code: def by_population(self,
                        lower=-1,
                        upper=2 ** 31,
                        zipcode_type=ZipcodeType.Standard,
                        sort_by=SimpleZipcode.population.name,
                        ascending=False,
                        returns=DEFAULT_LIMIT):
          
          return self.query(
              population_lower=lower,
              population_upper=upper,
              sort_by=sort_by, zipcode_type=zipcode_type,
              ascending=ascending, returns=returns,
          )
docs: Search zipcode information by population range.