code: def default_validator(completion, prefix):
      return completion.startswith(prefix)
  
imports: import argparse
  import os
  import sys
  from collections.abc import Mapping
  from typing import Callable, Dict, List, Optional, Sequence, Union
  from .None import io
  from .completers import ChoicesCompleter, FilesCompleter, SuppressCompleter
  from .io import debug, mute_stderr
  from .lexers import split_line
  from .packages._argparse import IntrospectiveArgumentParser, action_is_greedy, action_is_open, action_is_satisfied
label_desc: Use image node_id 1 for calling a global function with example usage: default_validator(completion, prefix) and returns: completion