input: def generate_top_books_html(genre: str) -> str:
      """Generate 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>10000</td></tr><tr><td>Title2</td><td>Author2</td><td>Fantasy</td><td>9000</td></tr><tr><td>Title3</td><td>Author3</td><td>Fantasy</td><td>8000</td></tr><tr><td>Title4</td><td>Author4</td><td>Fantasy</td><td>7000</td></tr><tr><td>Title5</td><td>Author5</td><td>Fantasy</td><td>6000</td></tr><tr><td>Title6</td><td>Author6</td><td>Fantasy</td><td>5000</td></tr><tr><td>Title7</td><td>Author7</td><td>Fantasy</td><td>4000</td></tr><tr><td>Title8</td><td>Author8</td><td>Fantasy</td><td>3000</td></tr><tr><td>Title9</td><td>Author9</td><td>Fantasy</td><td>2000</td></tr><tr><td>Title10</td><td>Author10</td><td>Fantasy</td><td>1000</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>{11000 - i * 1000}</td></tr>'
      html += '</table>'
      return html