code: def buildkite_group(
      name: str,
      open: Optional[bool] = None,
      print_fn: Callable[[str], None] = print,
  ):
      if open is True:
          buildkite_echo(f"+++ {name}", print_fn=print_fn)
      elif open is False:
          buildkite_echo(f"~~~ {name}", print_fn=print_fn)
      else:  # None
          buildkite_echo(f"--- {name}", print_fn=print_fn)
  
imports: import os
  from typing import Optional, Callable
label_desc: Use image node_id 2 for calling a global function with example usage: buildkite_group(name, open, print_fn) without return types