code: public Retrofit.Builder create(String baseUrl, ObjectMapper objectMapper) {
          return new Retrofit.Builder()
                  .baseUrl(baseUrl)
                  .client(_okHttpClient)
                  .addConverterFactory(JacksonConverterFactory.create(objectMapper));
      }
docs: Creates a new builder instance with the provided base url. Initialized with a Jackson JSON converter using the
  provided object mapper.
  
  @param baseUrl      the base url
  @param objectMapper the object mapper
  @return a builder instance initialized for use with service classes