nodes: 0, module; 1, function_definition; 2, function_name:_fetch_events_files_on_disk; 3, parameters; 4, block; 5, identifier:self; 6, expression_statement; 7, expression_statement; 8, expression_statement; 9, return_statement; 10, comment:"""Obtains the names of debugger-related events files within the directory.
  
      Returns:
        The names of the debugger-related events files written to disk. The names
        are sorted in increasing events file index.
      """; 11, assignment; 12, assignment; 13, call; 14, identifier:all_files; 15, call; 16, identifier:relevant_files; 17, list_comprehension; 18, identifier:sorted; 19, argument_list; 20, attribute; 21, argument_list; 22, identifier:file_name; 23, for_in_clause; 24, if_clause; 25, identifier:relevant_files; 26, keyword_argument; 27, attribute; 28, identifier:listdir; 29, attribute; 30, identifier:file_name; 31, identifier:all_files; 32, call; 33, identifier:key; 34, attribute; 35, attribute; 36, identifier:gfile; 37, identifier:self; 38, identifier:_events_directory; 39, attribute; 40, argument_list; 41, identifier:self; 42, identifier:_obtain_file_index; 43, identifier:tf; 44, identifier:io; 45, identifier:_DEBUGGER_EVENTS_FILE_NAME_REGEX; 46, identifier:match; 47, identifier:file_name
code: def _fetch_events_files_on_disk(self):
      """Obtains the names of debugger-related events files within the directory.
  
      Returns:
        The names of the debugger-related events files written to disk. The names
        are sorted in increasing events file index.
      """
      all_files = tf.io.gfile.listdir(self._events_directory)
      relevant_files = [
          file_name for file_name in all_files
          if _DEBUGGER_EVENTS_FILE_NAME_REGEX.match(file_name)
      ]
      return sorted(relevant_files, key=self._obtain_file_index)