build/lib/i18n.ts/is
	export function is(value: any): value is PackageJsonFormat {
		if (Is.undef(value) || !Is.object(value)) {
			return false;
		}
		return Object.keys(value).every(key => {
			const element = value[key];
			return Is.string(element) || (Is.object(element) && Is.defined(element.message) && Is.defined(element.comment));
		});
	}