input: 
  import re
  
  # Clean a string of HTML tags 
  def clean_html_tags(str: str) -> str:
      """
      Remove HTML tags from a given string.
      >>> clean_html_tags("<p>This is a <b>test</b> string</p>")
      'This is a test string'
      >>> clean_html_tags("<div><h1>Title</h1><p>Paragraph</p></div>")
      'TitleParagraph'
      """
      clean_str = re.sub("<.*?>", "", str)
      return clean_str
  
output:     clean_str = re.sub("<.*?>", "", str)
      return clean_str