public function endpoint_args() {
		return [
			'id' => [
				'default' => false,
				'validate_callback' => function ( $id ) {
					return false === $id || intval( $id ) > 0;
				},
			],
			'slug' => [
				'default' => false,
				'sanitize_callback' => function ( $slug, $request, $key ) {
					return false === $slug ? $slug : sanitize_text_field( $slug );
				},
			],
		];
	}