WP_REST_Posts_Controller::check_template( string $template, WP_REST_Request $request ): true|WP_Error

1601	public function check_template( $template, $request ) {1602 1603		if ( ! $template ) {1604			return true;1605		}1606 1607		if ( $request['id'] ) {1608			$post             = get_post( $request['id'] );1609			$current_template = get_page_template_slug( $request['id'] );1610		} else {1611			$post             = null;1612			$current_template = '';1613		}1614 1615		// Always allow for updating a post to the same template, even if that template is no longer supported.1616		if ( $template === $current_template ) {1617			return true;1618		}1619 1620		// If this is a create request, get_post() will return null and wp theme will fallback to the passed post type.1621		$allowed_templates = wp_get_theme()->get_page_templates( $post, $this->post_type );1622 1623		if ( isset( $allowed_templates[ $template ] ) ) {1624			return true;1625		}1626 1627		return new WP_Error(1628			'rest_invalid_param',1629			/* translators: 1: Parameter, 2: List of valid values. */1630			sprintf( __( '%1$s is not one of %2$s.' ), 'template', implode( ', ', array_keys( $allowed_templates ) ) )1631		);1632	}