Do I need to write a raw comparator for a Writable collection class?

[W.P. McNeill]

I have a custom MyWritable < Writable object for which I have written a
custom WritableComparator. I am putting MyWritable inside a MyArrayWritable
< ArrayWritable so that I can use lists of these objects as MapReduce keys.
Do I need to write a custom comparator for MyArrayWritable too?

>From looking at the source, it appears the answer is yes, but I wanted to
double-check, because it seems like there could be a generic implementation.