update city

src/classes/magic_stone.py

@@ -1,5 +1,7 @@
 
 
+from typing import Union
+
 class MagicStone(int):
     """
     灵石，实际上是一个int类，代表持有的下品灵石的数量。
@@ -15,4 +17,14 @@ class MagicStone(int):
 
     def __str__(self) -> str:
         _upper, _middle, _value = self.exchange()
-        return f"上品灵石：{_upper}，中品灵石：{_middle}，下品灵石：{_value}"
+        return f"上品灵石：{_upper}，中品灵石：{_middle}，下品灵石：{_value}"
+
+    def __add__(self, other: Union['MagicStone', int]) -> 'MagicStone':
+        if isinstance(other, int):
+            return MagicStone(self.value + other)
+        return MagicStone(self.value + other.value)
+
+    def __sub__(self, other: Union['MagicStone', int]) -> 'MagicStone':
+        if isinstance(other, int):
+            return MagicStone(self.value - other)
+        return MagicStone(self.value - other.value)