WP_Error::add() WordPress Method

	public function add( $code, $message, $data = '' ) {
		$this->errors[ $code ][] = $message;

		if ( ! empty( $data ) ) {
			$this->add_data( $data, $code );
		}

		/**
		 * Fires when an error is added to a WP_Error object.
		 *
		 * @since 5.6.0
		 *
		 * @param string|int $code     Error code.
		 * @param string     $message  Error message.
		 * @param mixed      $data     Error data. Might be empty.
		 * @param WP_Error   $wp_error The WP_Error object.
		 */
		do_action( 'wp_error_added', $code, $message, $data, $this );
	}