public function mergeFiles($files, $config = [])
    {
        $configs = array_map(function ($f) { return require($f); }, $files);
        $configs[] = $config;
        return call_user_func_array('yii\helpers\ArrayHelper::merge', $configs);
    }
public function mergeFiles($files, $config = [])
    {
        $configs = array_map(function ($f) { return require($f); }, $files);
        $configs[] = $config;
        return call_user_func_array('yii\helpers\ArrayHelper::merge', $configs);
    }
public function mergeFiles ( $ files , $ config = [ ] ) { $ configs = array_map ( function ( $ f ) { return require ( $ f ) ; } , $ files ) ; $ configs [ ] = $ config ; return call_user_func_array ( 'yii\helpers\ArrayHelper::merge' , $ configs ) ; }
Load configuration files and merge them together.

The files are loaded in the context of this class. So you can use `$this`
and `self` to access instance / class methods.

@param array $files list of configuration files to load and merge.
Configuration from later files will override earlier values.
@param array $config additional configuration to merge into the result
@return array the resulting configuration array
Load configuration files and merge them together .