WP_Post::filter( string $filter )

Source

File: wp-includes/class-wp-post.php

public function filter( $filter ) {
		if ( $this->filter === $filter ) {
			return $this;
		}

		if ( 'raw' === $filter ) {
			return self::get_instance( $this->ID );
		}

		return sanitize_post( $this, $filter );
	}