default T6 getOrNull6() {
        return get6().orElse(null);
    }
Returns the 6th element from this tuple or {@code null} if no such
element is present.

@return the 6th element from this tuple or {@code null} if no such
        element is present.
common-parent/tuple/src/main/java/com/speedment/common/tuple/mutable/MutableTuple8.java