code: def split_by(
      items: List[str], separator: Optional[str] = None
  ) -> Tuple[List[str], List[str]]:
      """If the separator is present in the list, returns a 2-tuple of
  
      - the items before the separator,
      - all items after the separator.
  
      If the separator isn't present, returns a tuple of
  
      - (the original list, [])
  
      """
      if separator is None:
          separator = "--"
  
      try:
          idx = items.index(separator)
          return items[0:idx], items[idx + 1 :]
      except ValueError:
          return (items, [])
  
imports: import getpass
  import itertools
  import os
  import platform
  import sys
  from enum import Enum
  from typing import Any, Callable, Dict, Iterable, List, NamedTuple, Optional, Set, Tuple, Union
  from blessings import Terminal
  from pkg_resources import resource_filename
label_desc: Use image node_id 14 for calling a global function with example usage: split_by(items, separator) and returns: items,  items, items,  list