input: 
  def html_to_text(html_string: str) -> str:
      """Converts an HTML string to plain text by stripping out all HTML tags.
      
      >>> html_to_text("<p>Hello, <b>world</b>!</p>")
      'Hello, world!'
      >>> html_to_text("<div>This is a <a href='#'>link</a>.</div>")
      'This is a link.'
      """
      output = ''
      in_tag = False
      for char in html_string:
          if char == '<':
              in_tag = True
          elif char == '>':
              in_tag = False
          elif not in_tag:
              output += char
      return output
  
output:     output = ''
      in_tag = False
      for char in html_string:
          if char == '<':
              in_tag = True
          elif char == '>':
              in_tag = False
          elif not in_tag:
              output += char
      return output