code: def hdepth(tag):
    
    if not _heading_re.search(tag.name):
      raise TaskError("Can't compute heading depth of non-heading {}".format(tag))
    depth = int(tag.name[1], 10)  # get the 2 from 'h2'
    cursor = tag
    while cursor:
      if cursor.name == 'section':
        depth += 1
      cursor = cursor.parent
    return depth
docs: Compute an h tag's "outline depth".
  
    E.g., h1 at top level is 1, h1 in a section is 2, h2 at top level is 2.