def _get_added_comment_id(src):
  """Returns comment ID from given request."""
  if not src:
    return None

  actions = src.get('actions') or {}
  related = actions.get('add_related') or []

  if not related:
    return None

  related_obj = related[0]

  if related_obj.get('type') != 'Comment':
    return None

  return related_obj.get('id')