How to use the yapf.yapflib.pytree_utils.Annotation function in yapf

def _SetMustSplitOnFirstLeaf(node):
  """Set the "must split" annotation on the first leaf node."""
  pytree_utils.SetNodeAnnotation(
      pytree_utils.FirstLeafNode(node), pytree_utils.Annotation.MUST_SPLIT,
      True)

tree: root of a pytree. The pytree is modified to add annotations to nodes.

  Raises:
    RuntimeError: if the tree is malformed.
  """
  # Annotate the root of the tree with zero indent.
  if tree.parent is None:
    pytree_utils.SetNodeAnnotation(tree, pytree_utils.Annotation.CHILD_INDENT,
                                   '')
  for child in tree.children:
    if child.type == token.INDENT:
      child_indent = pytree_utils.GetNodeAnnotation(
          tree, pytree_utils.Annotation.CHILD_INDENT)
      if child_indent is not None and child_indent != child.value:
        raise RuntimeError('inconsistent indentation for child', (tree, child))
      pytree_utils.SetNodeAnnotation(tree, pytree_utils.Annotation.CHILD_INDENT,
                                     child.value)
    _AnnotateIndents(child)

def RemoveSubtypeAnnotation(node, value):
  """Removes an annotation value from the subtype annotations on the node.

  Arguments:
    node: the node.
    value: annotation value to remove.
  """
  attr = GetNodeAnnotation(node, Annotation.SUBTYPE)
  if attr and value in attr:
    attr.remove(value)
    SetNodeAnnotation(node, Annotation.SUBTYPE, attr)

def _DecrementSplitPenalty(node, amt):
  penalty = pytree_utils.GetNodeAnnotation(
      node, pytree_utils.Annotation.SPLIT_PENALTY, default=amt)
  penalty = penalty - amt if amt < penalty else 0
  _SetSplitPenalty(node, penalty)

def _AdjustSplitPenalty(uwline):
  """Visit the node and adjust the split penalties if needed.

  A token shouldn't be split if it's not within a bracket pair. Mark any token
  that's not within a bracket pair as "unbreakable".

  Arguments:
    uwline: (UnwrappedLine) An unwrapped line.
  """
  bracket_level = 0
  for index, token in enumerate(uwline.tokens):
    if index and not bracket_level:
      pytree_utils.SetNodeAnnotation(token.node,
                                     pytree_utils.Annotation.SPLIT_PENALTY,
                                     split_penalty.UNBREAKABLE)
    if token.value in pytree_utils.OPENING_BRACKETS:
      bracket_level += 1
    elif token.value in pytree_utils.CLOSING_BRACKETS:
      bracket_level -= 1

like "  ") of its children. It is inferred from the INDENT child of a node.

  Arguments:
    tree: root of a pytree. The pytree is modified to add annotations to nodes.

  Raises:
    RuntimeError: if the tree is malformed.
  """
  # Annotate the root of the tree with zero indent.
  if tree.parent is None:
    pytree_utils.SetNodeAnnotation(tree, pytree_utils.Annotation.CHILD_INDENT,
                                   '')
  for child in tree.children:
    if child.type == token.INDENT:
      child_indent = pytree_utils.GetNodeAnnotation(
          tree, pytree_utils.Annotation.CHILD_INDENT)
      if child_indent is not None and child_indent != child.value:
        raise RuntimeError('inconsistent indentation for child', (tree, child))
      pytree_utils.SetNodeAnnotation(tree, pytree_utils.Annotation.CHILD_INDENT,
                                     child.value)
    _AnnotateIndents(child)

def _MustBreakBefore(prev_token, cur_token):
  """Return True if a line break is required before the current token."""
  if prev_token.is_comment or (prev_token.previous_token and
                               prev_token.is_pseudo_paren and
                               prev_token.previous_token.is_comment):
    # Must break if the previous token was a comment.
    return True
  if (cur_token.is_string and prev_token.is_string and
      IsSurroundedByBrackets(cur_token)):
    # We want consecutive strings to be on separate lines. This is a
    # reasonable assumption, because otherwise they should have written them
    # all on the same line, or with a '+'.
    return True
  return pytree_utils.GetNodeAnnotation(
      cur_token.node, pytree_utils.Annotation.MUST_SPLIT, default=False)

def _AppendTokenSubtype(node, subtype):
  """Append the token's subtype only if it's not already set."""
  pytree_utils.AppendNodeAnnotation(node, pytree_utils.Annotation.SUBTYPE,
                                    subtype)

index -= 1
          if final_lines[index - 1].first.value == '@':
            final_lines[index].first.AdjustNewlinesBefore(NO_BLANK_LINES)
          else:
            prev_last_token.AdjustNewlinesBefore(
                1 + style.Get('BLANK_LINES_AROUND_TOP_LEVEL_DEFINITION'))
          if first_token.newlines is not None:
            pytree_utils.SetNodeAnnotation(first_token.node,
                                           pytree_utils.Annotation.NEWLINES,
                                           None)
          return NO_BLANK_LINES
    elif _IsClassOrDef(prev_uwline.first):
      if first_nested and not style.Get(
          'BLANK_LINE_BEFORE_NESTED_CLASS_OR_DEF'):
        pytree_utils.SetNodeAnnotation(first_token.node,
                                       pytree_utils.Annotation.NEWLINES, None)
        return NO_BLANK_LINES

  # Calculate how many newlines were between the original lines. We want to
  # retain that formatting if it doesn't violate one of the style guide rules.
  if first_token.is_comment:
    first_token_lineno = first_token.lineno - first_token.value.count('\n')
  else:
    first_token_lineno = first_token.lineno

  prev_last_token_lineno = prev_last_token.lineno
  if prev_last_token.is_multiline_string:
    prev_last_token_lineno += prev_last_token.value.count('\n')

  if first_token_lineno - prev_last_token_lineno > 1:
    return ONE_BLANK_LINE