code: def check_for_files_failed(self):
          
          if len(config.FAILED_FILES) > 0:
              config.LOGGER.error("   {} file(s) have failed to download".format(len(config.FAILED_FILES)))
              for f in config.FAILED_FILES:
                  title = "{0} {id}".format(f.node.kind.capitalize(), id=f.node.source_id)\
                          if f.node else "{0} {id}".format("Question", id=f.assessment_item.source_id)
                  file_identifier = f.__dict__
                  if hasattr(f, 'path') and f.path:
                      file_identifier = f.path
                  elif hasattr(f, 'youtube_url') and f.youtube_url:
                      file_identifier = f.youtube_url
                  config.LOGGER.warning("\t{0}: {id} \n\t   {err}".format(title, id=file_identifier, err=f.error))
          else:
              config.LOGGER.info("   All files were successfully downloaded")
docs: check_for_files_failed: print any files that failed during download process
              Args: None
              Returns: None