code: public static <T extends StripeCollectionInterface<?>> T requestCollection(
        String url, Map<String, Object> params, Class<T> clazz,
        RequestOptions options)
        throws StripeException {
      T collection = request(RequestMethod.GET, url, params, clazz, options);
  
      if (collection != null) {
        collection.setRequestOptions(options);
        collection.setRequestParams(params);
      }
  
      return collection;
    }
docs: Similar to #request, but specific for use with collection types that
  come from the API (i.e. lists of resources).
  
  <p>Collections need a little extra work because we need to plumb request
  options and params through so that we can iterate to the next page if
  necessary.