code: public BoxRequestsMetadata.AddItemMetadata getAddFolderMetadataRequest(String id, LinkedHashMap<String, Object> values, String scope, String template) {
          BoxRequestsMetadata.AddItemMetadata request = new BoxRequestsMetadata.AddItemMetadata(values, getFolderMetadataUrl(id, scope, template), mSession);
          return request;
      }
docs: Gets a request that adds metadata to a folder
  
  @param id    id of the folder to add metadata to
  @param values    mapping of the template keys to their values
  @param scope    currently only global and enterprise scopes are supported
  @param template    metadata template to use
  @return  request to add metadata to a folder