<p>Looks great to me.  I added a test to serialize empty cubes in <a href="https://github.com/mlpack/mlpack/commit/8653bf1243fe9daa7e0a75dacf3a4a510d27b5ae" class="commit-link"><tt>8653bf1</tt></a> and then removed the XMLs from the test names in <a href="https://github.com/mlpack/mlpack/commit/0603d2e4e83e96e518157b99ce5a28375b96006f" class="commit-link"><tt>0603d2e</tt></a>.  (No actual code was changed.)</p>

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