code: def child_towards(ancestor: Node, descendant: LN) -> Optional[LN]:
      """Return the child of `ancestor` that contains `descendant`."""
      node: Optional[LN] = descendant
      while node and node.parent != ancestor:
          node = node.parent
      return node
  
imports: import sys
  from typing import Final, Generic, Iterator, List, Optional, Set, Tuple, TypeVar, Union
  from mypy_extensions import mypyc_attr
  from black.cache import CACHE_DIR
  from black.mode import Mode, Preview
  from black.strings import get_string_prefix, has_triple_quotes
  from blib2to3 import pygram
  from blib2to3.pgen2 import token
  from blib2to3.pytree import NL, Leaf, Node, type_repr
label_desc: Use image node_id 6 for calling a global function with example usage: child_towards(ancestor, descendant) and returns: node