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 function should connect to the database, retrieve the data for the specified genre ordered by sales in descending order, and generate an HTML table with columns for Title, Author, Genre, and Sales. If the database contains no books in the specified genre, the function should return an HTML paragraph stating "No books found in the specified genre."
  assert generate_html_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>5000</td></tr></table>'
  assert generate_html_table('Science Fiction')=='<p>No books found in the specified genre.</p>'
  assert generate_html_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>3000</td></tr></table>'
  assert generate_html_table('Romance')=='<p>No books found in the specified genre.</p>'
output: def generate_html_table(genre):
      import sqlite3
      conn = sqlite3.connect('books.db')
      cursor = conn.cursor()
      cursor.execute("SELECT Title, Author, Genre, Sales FROM books WHERE Genre=? ORDER BY Sales DESC LIMIT 10", (genre,))
      rows = cursor.fetchall()
      conn.close()
      
      if not rows:
          return '<p>No books found in the specified genre.</p>'
      
      html = '<table><tr><th>Title</th><th>Author</th><th>Genre</th><th>Sales</th></tr>'
      for row in rows:
          html += f'<tr><td>{row[0]}</td><td>{row[1]}</td><td>{row[2]}</td><td>{row[3]}</td></tr>'
      html += '</table>'
      return html