code: protected function getTableGateway($tableName)
      {
          if (!array_key_exists($tableName, $this->tableGateways)) {
              $acl = TableSchema::getAclInstance();
              $this->tableGateways[$tableName] = new RelationalTableGateway($tableName, $this->connection, $acl);
          }
  
          return $this->tableGateways[$tableName];
      }
docs: Get a table gateway for the given table name
  
  @param $tableName
  
  @return RelationalTableGateway