code: public <OUT> DataStreamSource<OUT> addSource(SourceFunction<OUT> function, TypeInformation<OUT> typeInfo) {
  		return addSource(function, "Custom Source", typeInfo);
  	}
docs: Ads a data source with a custom type information thus opening a
  {@link DataStream}. Only in very special cases does the user need to
  support type information. Otherwise use
  {@link #addSource(org.apache.flink.streaming.api.functions.source.SourceFunction)}
  
  @param function
  the user defined function
  @param <OUT>
  type of the returned stream
  @param typeInfo
  the user defined type information for the stream
  @return the data stream constructed