input: from typing import List, Dict
  
  def html_to_text(html_string: str) -> str:
      """ Converts an HTML string to plain text by removing all HTML tags.
      >>> html_to_text('<h1>Hello, World!</h1>')
      'Hello, World!'
      >>> html_to_text('<span>This is a <b>bold</b> text.</span>')
      'This is a bold text.'
      """
output:     import re
      return re.sub(r'<[^>]+>', '', html_string)