code: public function save($file, $name, $options = [])
  	{
  		$name = ltrim($name, DIRECTORY_SEPARATOR);
  		
  		if ($folder = trim(ArrayHelper::getValue($options, 'folder'), DIRECTORY_SEPARATOR)) {
  			$name = $folder . DIRECTORY_SEPARATOR . $name;
  		}
  		
  		if (!ArrayHelper::getValue($options, 'override', true) && $this->fileExists($name)) {
  			return false;
  		}
  		
  		$path = $this->getBasePath() . DIRECTORY_SEPARATOR . $name;
  		@mkdir(dirname($path), 0777, true);
  
  		return $file->saveAs($path);
  	}
docs: Saves a file
  @param \yii\web\UploadedFile $file the file uploaded
  @param string $name the name of the file. If empty, it will be set to the name of the uploaded file
  @param array $options to save the file. The options can be any of the following:
  - `folder` : whether we should create a subfolder where to save the file
  - `override` : whether we allow rewriting a existing file
  @return boolean