input: 
  def generate_top_books_html(genre: str) -> str:
      """ Generates an HTML table displaying information about the top 10 bestselling books in the specified genre.
      >>> generate_top_books_html('Fantasy')
      '<table><tr><th>Title</th><th>Author</th><th>Genre</th><th>Sales</th></tr><tr><td>Title1</td><td>Author1</td><td>Fantasy</td><td>100</td></tr><tr><td>Title2</td><td>Author2</td><td>Fantasy</td><td>90</td></tr><tr><td>Title3</td><td>Author3</td><td>Fantasy</td><td>80</td></tr><tr><td>Title4</td><td>Author4</td><td>Fantasy</td><td>70</td></tr><tr><td>Title5</td><td>Author5</td><td>Fantasy</td><td>60</td></tr><tr><td>Title6</td><td>Author6</td><td>Fantasy</td><td>50</td></tr><tr><td>Title7</td><td>Author7</td><td>Fantasy</td><td>40</td></tr><tr><td>Title8</td><td>Author8</td><td>Fantasy</td><td>30</td></tr><tr><td>Title9</td><td>Author9</td><td>Fantasy</td><td>20</td></tr><tr><td>Title10</td><td>Author10</td><td>Fantasy</td><td>10</td></tr></table>'
      """
  
output:     
      html = '<table><tr><th>Title</th><th>Author</th><th>Genre</th><th>Sales</th></tr>'
      for i in range(1, 11):
          html += f'<tr><td>Title{i}</td><td>Author{i}</td><td>{genre}</td><td>{110 - i * 10}</td></tr>'
      html += '</table>'
      return html
  