input: 
  def item_representation(item):
      """ Given an instance of the StoreItem class, return a string representation of the item.
      >>> item = StoreItem(1, "Laptop", 999.99, "High performance laptop")
      >>> item_representation(item)
      'Laptop, $999.99'
      """
  
output:     return f"{item.name}, ${item.price:.2f}"