code: private String doFindEquivalence(final String destinationNamespace,
              final SkinnyUUID sourceUUID) {
          JDBMEquivalenceLookup destinationLookup = openEquivalences
                  .get(destinationNamespace);
  
          return destinationLookup.reverseLookup(sourceUUID);
      }
docs: Obtain the destinationNamespace equivalent value of the sourceUUID.
  @param destinationNamespace resourceLocation of destination namespace
  @param sourceUUID
  @return equivalent value, may be null