docs: public CreateDocumentResponse createDocument(File file, String title) {
          CreateDocumentRequest request = new CreateDocumentRequest();
          String format;
          String filename = file.getName();
          if (filename.lastIndexOf(".") == -1) {
              throw new BceClientException("Cannot get file format from file name:" + filename);
          }
          format = filename.substring(filename.lastIndexOf(".") + 1);
          request.setFile(file);
          request.setTitle(title);
          request.setFormat(format);
          return this.createDocument(request);
      }