input: import re
  
  def clean_html_tags(s: str) -> str:
      """ Clean a string of HTML tags.
      >>> clean_html_tags("<p>This is a <b>test</b> string</p>")
      'This is a test string'
      >>> clean_html_tags("<div>Hello <span>World</span></div>")
      'Hello World'
      """
      cleaned_str = re.sub(r"<.*?>", "", s)
      return cleaned_str
output:     cleaned_str = re.sub(r"<.*?>", "", s)
      return cleaned_str