Start working on cart system

src/Cart.py

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+from typing import final
+
+from PySide6.QtWidgets import QWidget
+from Movie import Movie
+from enum import Enum
+
+class ShopItemType(Enum):
+    """
+    Enum dictating types of items that can be bought from the cinema.
+    """
+    Movie = 0
+    Popcorn = 1
+    Frozen_Coke = 2
+
+@final
+class ShopItem:
+    """
+    Represents an item that can be bought from the cinema.
+    """
+    def __init__(self, type: ShopItemType, quantity: int, movie: Movie | None = None):
+        """
+        Creates a new ShopItem.
+        Throws:
+            ValueError - type is ShopItemType.Movie, but movie is not provided as a paramater
+        Example (creates a ShopItem with type popcorn and quantity 3):
+            ShopItem(ShopItemType.Popcorn, 3)
+        """
+        self.type = type
+        self.movie = movie
+        self.quantity = quantity
+        self.cost: float
+        match type:
+            case ShopItemType.Movie:
+                if movie != None:
+                    self.cost = movie.price
+                else:
+                    raise ValueError("ShopItem with type ShopItemType.Movie must provide a movie as an argument")
+            case ShopItemType.Popcorn:
+                self.cost = 9.95
+                pass
+            case ShopItemType.Frozen_Coke:
+                self.cost = 4.95
+
+@final
+class Cart:
+    def __init__(self):
+        self.contents: list[ShopItem] = []
+
+    def addItem(self, item: ShopItem):
+        self.contents.append(item)
+        pass
+
+cart = Cart()
+
+
+class CartView(QWidget):
+    def __init__(self):
+        super().__init__()
+        global cart
+        self.setWindowTitle("Work in progress!")
+