code: def get_file_diff(self, files_to_diff):
          
          file_diff_result = []
          chunks = [files_to_diff[x:x+1000] for x in range(0, len(files_to_diff), 1000)]
          file_count = 0
          total_count = len(files_to_diff)
          for chunk in chunks:
              response = config.SESSION.post(config.file_diff_url(), data=json.dumps(chunk))
              response.raise_for_status()
              file_diff_result += json.loads(response._content.decode("utf-8"))
              file_count += len(chunk)
              config.LOGGER.info("\tGot file diff for {0} out of {1} files".format(file_count, total_count))
  
          return file_diff_result
docs: get_file_diff: retrieves list of files that do not exist on content curation server
              Args: None
              Returns: list of files that are not on server