code: public <T extends Dto> T request(Class<T> classOfT, String idempotencyKey, String urlMethod, String requestType) throws Exception {
          return request(classOfT, idempotencyKey, urlMethod, requestType, null, null, null);
      }
docs: Makes a call to the MangoPay API.
  <p>
  This generic method handles calls targeting single
  <code>Dto</code> instances. In order to process collections of objects,
  use <code>requestList</code> method instead.
  
  @param <T>         Type on behalf of which the request is being called.
  @param classOfT    Type on behalf of which the request is being called.
  @param urlMethod   Relevant method key.
  @param requestType HTTP request term, one of the GET, PUT or POST.
  @return The Dto instance returned from API.
  @throws Exception