code: protected boolean valuesEqual(MapEntryValue oldValue, MapEntryValue newValue) {
      return (oldValue == null && newValue == null)
          || (oldValue != null && newValue != null && valuesEqual(oldValue.value(), newValue.value()));
    }
docs: Returns a boolean indicating whether the given MapEntryValues are equal.
  
  @param oldValue the first value to compare
  @param newValue the second value to compare
  @return indicates whether the two values are equal