input: from typing import List, Tuple
  
  
  def generate_html_table(books: List[Tuple[str, str, str, int]]) -> str:
      """Generate an HTML table displaying information about the top 10 bestselling books in a specific genre.
      The input is a list of tuples, where each tuple contains the title, author, genre, and sales of a book.
      >>> generate_html_table([('The Hobbit', 'J.R.R. Tolkien', 'Fantasy', 100), ('Harry Potter', 'J.K. Rowling','Fantasy', 90)])
      '<table><tr><th>Title</th><th>Author</th><th>Genre</th><th>Sales</th></tr><tr><td>The Hobbit</td><td>J.R.R. Tolkien</td><td>Fantasy</td><td>100</td></tr><tr><td>Harry Potter</td><td>J.K. Rowling</td><td>Fantasy</td><td>90</td></tr></table>'
      """
output:     html = "<table><tr><th>Title</th><th>Author</th><th>Genre</th><th>Sales</th></tr>"
      for book in books:
          title, author, genre, sales = book
          html += f"<tr><td>{title}</td><td>{author}</td><td>{genre}</td><td>{sales}</td></tr>"
      html += "</table>"
      return html