docs: public static Map<String, String> demapProperties(
              final Map<String, String> input,
              final Map<String, String> mapping,
              final boolean skip
      )
      {
          if (null == mapping) {
              return input;
          }
          final Map<String, String> rev = new HashMap<String, String>();
          for (final Map.Entry<String, String> entry : mapping.entrySet()) {
              rev.put(entry.getValue(), entry.getKey());
          }
          return performMapping(input, rev, skip);
      }