input: Write a function to generate an HTML table displaying information about the top 10 bestselling books in a specific genre. The function should accept a genre as an argument and return the HTML code of the table.
  
  
  assert generate_bestseller_table('Fantasy') == '''<table>
  <tr><th>Title</th><th>Author</th><th>Genre</th><th>Sales</th></tr>
  </table>'''
  assert generate_bestseller_table('Mystery') == '''<table>
  <tr><th>Title</th><th>Author</th><th>Genre</th><th>Sales</th></tr>
  </table>'''
  assert generate_bestseller_table('Romance') == '''<table>
  <tr><th>Title</th><th>Author</th><th>Genre</th><th>Sales</th></tr>
  </table>'''
  
output: def generate_bestseller_table(genre):
      return '''<table>
  <tr><th>Title</th><th>Author</th><th>Genre</th><th>Sales</th></tr>
  </table>'''