League\CommonMark\Util\Configuration::mergeConfig PHP Method

    public function mergeConfig(array $config = [])
    {
        $this->config = array_replace_recursive($this->config, $config);
    }

 /**
  * @param array $config
  */
 public function mergeConfig(array $config = [])
 {
     $this->assertUninitialized('Failed to modify configuration.');
     $this->config->mergeConfig($config);
 }