code: public <T> Optional<T> GET(String partialUrl, GenericType<T> returnType)
      {    
          URI uri = buildUri(partialUrl);   
          return executeGetRequest(uri, returnType);
      }
docs: Execute a GET call against the partial URL and deserialize the results.
  @param <T> The type parameter used for the return object
  @param partialUrl The partial URL to build
  @param returnType The expected return type
  @return The return type