apply_filters( 'post_playlist', string $output, array $attr, int $instance )

3216	 * @since 4.2.0 The `$instance` parameter was added.3217	 *3218	 * @param string $output   Playlist output. Default empty.3219	 * @param array  $attr     An array of shortcode attributes.3220	 * @param int    $instance Unique numeric ID of this playlist shortcode instance.3221	 */3222	$output = apply_filters( 'post_playlist', '', $attr, $instance );3223 3224	if ( ! empty( $output ) ) {3225		return $output;3226	}3227 3228	$atts = shortcode_atts(