code: public function join(
          $table,
          $firstTableCol = '',
          /*# string */ $operator = ClauseInterface::NO_OPERATOR,
          /*# string */ $secondTableCol = ClauseInterface::NO_VALUE
      ) {
          return $this->realJoin('INNER', $table, $firstTableCol, $operator,
              $secondTableCol);
      }
docs: {@inheritDoc}