@Override
        public S getF4() {
            return null;
        }
<p>A triple consisting of four elements.</p>

<p>This class is an abstract implementation defining the basic API.
It refers to the elements as 'f1', 'f2' , 'f3' and 'f4'.</p>

<p>Subclass implementations may be mutable or immutable.
However, there is no restriction on the type of the stored objects that may be stored.
If mutable objects are stored in the triple, then the triple itself effectively becomes mutable.</p>

@param <L> the f1 element type
@param <M> the f2 element type
@param <R> the f3 element type
@param <S> the f4 element type
inlong-manager/manager-common/src/main/java/org/apache/inlong/manager/common/tool/excel/tuple/Quartet.java