code: @PublicEvolving
  	static <T extends Writable> TypeInformation<T> getWritableTypeInfo(Class<T> typeClass) {
  		if (Writable.class.isAssignableFrom(typeClass) && !typeClass.equals(Writable.class)) {
  			return new WritableTypeInfo<T>(typeClass);
  		}
  		else {
  			throw new InvalidTypesException("The given class is no subclass of " + Writable.class.getName());
  		}
  	}
docs: --------------------------------------------------------------------------------------------