code: public String getMFS(final TreeMultimap<Integer, String> mfsMap) {
      final SortedSet<String> mfs = mfsMap.get(mfsMap.keySet().first());
      return mfs.first();
    }
docs: Get the MFS from a lemma#posClass entry, e.g., house#n.
  
  @param mfsMap
  map to get the MFS from
  @return the most frequent sense