docs: @PublicEvolving
  	@Deprecated
  	public <R, ACC> SingleOutputStreamOperator<R> fold(ACC initialValue, FoldFunction<T, ACC> foldFunction, ProcessWindowFunction<ACC, R, K, W> windowFunction) {
  		if (foldFunction instanceof RichFunction) {
  			throw new UnsupportedOperationException("FoldFunction can not be a RichFunction.");
  		}
  
  		TypeInformation<ACC> foldResultType = TypeExtractor.getFoldReturnTypes(foldFunction, input.getType(),
  				Utils.getCallLocationName(), true);
  
  		TypeInformation<R> windowResultType = getProcessWindowFunctionReturnType(windowFunction, foldResultType, Utils.getCallLocationName());
  
  		return fold(initialValue, foldFunction, windowFunction, foldResultType, windowResultType);
  	}