code: def upload_files(self, file_list):
          
          counter = 0
          files_to_upload = list(set(file_list) - set(self.uploaded_files)) # In case restoring from previous session
          try:
              for f in files_to_upload:
                  with open(config.get_storage_path(f), 'rb') as file_obj:
                      response = config.SESSION.post(config.file_upload_url(), files={'file': file_obj})
                      if response.status_code == 200:
                          response.raise_for_status()
                          self.uploaded_files.append(f)
                          counter += 1
                          config.LOGGER.info("\tUploaded {0} ({count}/{total}) ".format(f, count=counter, total=len(files_to_upload)))
                      else:
                          self.failed_uploads[f] = response._content.decode('utf-8')
          finally:
              config.PROGRESS_MANAGER.set_uploading(self.uploaded_files)
docs: upload_files: uploads files to server
              Args:
                  file_list (str): list of files to upload
              Returns: None