code: def parse_int(s: str) -> int:
      """Parse a non-negative integer from a string."""
      if DIGITS.fullmatch(s) is None:
          raise ValueError("not an integer: %r" % s)
      return int(s)
  
imports: import asyncio
  import logging
  import re
  import types
  from tornado.concurrent import Future, future_add_done_callback, future_set_result_unless_cancelled
  from tornado.escape import native_str, utf8
  from tornado import gen
  from tornado import httputil
  from tornado import iostream
  from tornado.log import gen_log, app_log
  from tornado.util import GzipDecompressor
  from typing import cast, Optional, Type, Awaitable, Callable, Union, Tuple
label_desc: Use image node_id 1 for calling a global function with example usage: parse_int(s) and returns: int