code: def _try_cmd_notify_port():
      port = os.getenv("GUILD_CMD_NOTIFY_PORT")
      if not port:
          return None
      try:
          return int(port)
      except ValueError as e:
          raise SystemExit(
              f"invalid value for GUILD_CMD_NOTIFY_PORT {port!r}: must "
              "be a valid numeric port"
          ) from e
  
imports: import logging
  import os
  from guild import cli
  from guild import config
  from guild import log
label_desc: Use image node_id 16 for calling a global function with example usage: _try_cmd_notify_port() and returns: None, int