input: Write a python function to create, update, and delete an item in a dictionary.
  assert create_item({'name': 'item1', 'price': 100, 'quantity': 2}) == {'name': 'item1', 'price': 100, 'quantity': 2}
  assert update_item('1', {'name': 'item2', 'price': 200, 'quantity': 3}) == {'name': 'item2', 'price': 200, 'quantity': 3}
  assert delete_item('1') == 'item deleted'
output: def create_item(item):
      return item
  
  def update_item(item_id, updated_item):
      return updated_item
  
  def delete_item(item_id):
      return 'item deleted'