public function getDbalConnection(): Connection
 {
 if (false == $this->connection) {
 $connection = call_user_func($this->connectionFactory);
 if (false == $connection instanceof Connection) {
 throw new \LogicException(sprintf('The factory must return instance of Doctrine\DBAL\Connection. It returns %s', is_object($connection) ? $connection::class : gettype($connection)));
 }
 $this->connection = $connection;
 }
 return $this->connection;
 }