code: def write_functions(self, out: TextIO) -> None:
      if not self.functions:
          return
  
      out.write(
          f"""
  {_header('Functions', 1)}
  """
      )
      for function in self.functions:
          function.write(out)
  
imports: import inspect
  from dataclasses import dataclass
  from pathlib import Path
  from types import ModuleType
  from typing import Any, Callable, Deque, Dict, List, Mapping, Set, TextIO, Tuple, Type, Union
  from gpflow.utilities import Dispatcher
label_desc: Use image node_id 8 for calling the DocumentableModule obj's underlying member method code with example usage: obj.write_functions(out) without return types