input: def generate_bestselling_books_table(genre_name: str) -> str:
      """Generates an HTML table displaying information about the top 10 bestselling books in a specified genre.
      The function connects to a SQLite database called 'books.db' and retrieves data from a table named 'Books'.
      The 'Books' table contains columns: id (int), title (string), author (string), genre (string), sales (int).
      The results are ordered by sales in descending order and limited to the top 10.
      >>> generate_bestselling_books_table('Fantasy')
      '<table><tr><th>Title</th><th>Author</th><th>Genre</th><th>Sales</th></tr><tr><td>The Lord of the Rings</td><td>J.R.R. Tolkien</td><td>Fantasy</td><td>5000000</td></tr><tr><td>Game of Thrones</td><td>George R.R. Martin</td><td>Fantasy</td><td>4500000</td></tr></table>'
      """
output:     
      import sqlite3
  
      conn = sqlite3.connect('books.db')
      cursor = conn.cursor()
  
      query = f"""
      SELECT title, author, genre, sales
      FROM Books
      WHERE genre = ?
      ORDER BY sales DESC
      LIMIT 10
      """
  
      cursor.execute(query, (genre_name,))
      rows = cursor.fetchall()
  
      conn.close()
  
      if not rows:
          return ''
  
      table_html = '<table><tr><th>Title</th><th>Author</th><th>Genre</th><th>Sales</th></tr>'
      for row in rows:
          table_html += f'<tr><td>{row[0]}</td><td>{row[1]}</td><td>{row[2]}</td><td>{row[3]}</td></tr>'
      table_html += '</table>'
  
      return table_html
  