input: Write a function to generate an HTML table displaying information about the top 10 bestselling books in a specific genre from a SQLite database. The table should be named "Books" with columns id (int), title (string), author (string), genre (string), and sales (int). The function should return the HTML code as a string.
  
  def generate_bestseller_table(genre):
      import sqlite3
      # connect to the database
      conn = sqlite3.connect('books.db')
      c = conn.cursor()
  
      # retrieve the data
      c.execute('''SELECT title, author, genre, sales
      FROM Books
      WHERE genre=?
      ORDER BY sales DESC
      LIMIT 10''', (genre,))
  
      # save the results
      results = c.fetchall()
  
      # generate the HTML code
      html = '<table>'
      html += '<tr><th>Title</th><th>Author</th><th>Genre</th><th>Sales</th></tr>'
  
      for result in results:
          title = result[0]
          author = result[1]
          sales = result[3]
  
          html += f'<tr><td>{title}</td><td>{author}</td><td>{genre}</td><td>{sales}</td></tr>'
  
      html += '</table>'
  
      # return the HTML code
      return html
  
  assert generate_bestseller_table('Fantasy')=='<table><tr><th>Title</th><th>Author</th><th>Genre</th><th>Sales</th></tr><tr><td>Harry Potter</td><td>J.K. Rowling</td><td>Fantasy</td><td>1000000</td></tr></table>'
  assert generate_bestseller_table('Mystery')=='<table><tr><th>Title</th><th>Author</th><th>Genre</th><th>Sales</th></tr><tr><td>Sherlock Holmes</td><td>Arthur Conan Doyle</td><td>Mystery</td><td>900000</td></tr></table>'
  assert generate_bestseller_table('Romance')==''
  assert generate_bestseller_table('Science Fiction')==''
  assert generate_bestseller_table('')==''
output: def generate_bestseller_table(genre):
      import sqlite3
      conn = sqlite3.connect('books.db')
      c = conn.cursor()
      c.execute('''SELECT title, author, genre, sales
      FROM Books
      WHERE genre=?
      ORDER BY sales DESC
      LIMIT 10''', (genre,))
      results = c.fetchall()
      html = '<table>'
      html += '<tr><th>Title</th><th>Author</th><th>Genre</th><th>Sales</th></tr>'
      for result in results:
          title = result[0]
          author = result[1]
          sales = result[3]
          html += f'<tr><td>{title}</td><td>{author}</td><td>{genre}</td><td>{sales}</td></tr>'
      html += '</table>'
      return html