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 accept the genre as an input parameter and return the HTML table string. If no books are found for the given genre, return an empty string.
  assert generate_top_10_books_table('Fantasy')=='<table><tr><th>Title</th><th>Author</th><th>Genre</th><th>Sales</th></tr><tr><td>Example Title</td><td>Example Author</td><td>Fantasy</td><td>10000</td></tr></table>'
  assert generate_top_10_books_table('Science Fiction')==''
  assert generate_top_10_books_table('Mystery')=='<table><tr><th>Title</th><th>Author</th><th>Genre</th><th>Sales</th></tr><tr><td>Mystery Title</td><td>Mystery Author</td><td>Mystery</td><td>5000</td></tr></table>'
output: 
  def generate_top_10_books_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 ''
      
      html_table = '<table><tr><th>Title</th><th>Author</th><th>Genre</th><th>Sales</th></tr>'
      for row in rows:
          html_table += f'<tr><td>{row[0]}</td><td>{row[1]}</td><td>{row[2]}</td><td>{row[3]}</td></tr>'
      html_table += '</table>'
      
      return html_table
  