code: public ListDocumentsResponse listDocuments() {
          ListDocumentsRequest request = new ListDocumentsRequest();
          InternalRequest internalRequest = this.createRequest(HttpMethodName.GET, request, DOC);
          ListDocumentsResponse response;
          try {
              response = this.invokeHttpClient(internalRequest, ListDocumentsResponse.class);
          } finally {
              try {
                  internalRequest.getContent().close();
              } catch (Exception e) {
                  // ignore exception
              }
          }
  
          return response;
      }
docs: list all Document.
  
  
  @return A ListDocumentsResponse object containing the information returned by Document.