code: private static Gson getDeserializer(Map<Type, JsonDeserializer> deserializerMap) {
          GsonBuilder builder = new GsonBuilder();
  
          for (Map.Entry<Type, JsonDeserializer> entry : DESERIALIZER_MAP.entrySet()) {
              builder.registerTypeAdapter(entry.getKey(), entry.getValue());
          }
  
          for (Map.Entry<Type, JsonDeserializer> entry : deserializerMap.entrySet()) {
              builder.registerTypeAdapter(entry.getKey(), entry.getValue());
          }
          return builder.create();
      }
docs: ----- helper methods --------------------------------------------------