docs: public SingleOutputStreamOperator<T> returns(TypeHint<T> typeHint) {
  		requireNonNull(typeHint, "TypeHint must not be null");
  
  		try {
  			return returns(TypeInformation.of(typeHint));
  		}
  		catch (InvalidTypesException e) {
  			throw new InvalidTypesException("Cannot infer the type information from the type hint. " +
  					"Make sure that the TypeHint does not use any generic type variables.");
  		}
  	}