input: Write a python function to simulate a shopping cart with add, remove, and get total price functionalities.
  assert cart.get_total_price()==item1.price + item2.price + item4.price
  cart.add_item(item5)
  assert cart.get_total_price()==item1.price + item2.price + item4.price + item5.price
  cart.remove_item(item2)
  assert cart.get_total_price()==item1.price + item4.price + item5.price
output: class ShoppingCart:
      def __init__(self):
          self.items = []
  
      def add_item(self, item):
          self.items.append(item)
  
      def remove_item(self, item):
          self.items.remove(item)
  
      def get_total_price(self):
          return sum(item.price for item in self.items)
  
  # Example item class for testing purposes
  class Item:
      def __init__(self, name, price):
          self.name = name
          self.price = price
  
  # Test the ShoppingCart functionality
  cart = ShoppingCart()
  item1 = Item("item1", 10)
  item2 = Item("item2", 20)
  item4 = Item("item4", 40)
  item5 = Item("item5", 50)
  
  cart.add_item(item1)
  cart.add_item(item2)
  cart.add_item(item4)
  assert cart.get_total_price() == item1.price + item2.price + item4.price
  cart.add_item(item5)
  assert cart.get_total_price() == item1.price + item2.price + item4.price + item5.price
  cart.remove_item(item2)
  assert cart.get_total_price() == item1.price + item4.price + item5.price