add classy banking system solution

codewars/banking_system.py

@@ -0,0 +1,28 @@
+class User:
+    def __init__(self, name, balance, checking_account):
+        self.name = name
+        self.balance = balance
+        self.checking_account = checking_account
+        
+    def withdraw(self, amount):
+        if amount > self.balance:
+            raise ValueError("Not enough money")
+        
+        self.balance -= amount
+        return f"{self.name} has {self.balance}."
+        
+    def add_cash(self, amount):
+        self.balance += amount
+        return f"{self.name} has {self.balance}."
+        
+    def check(self, other_user, amount):
+        if not other_user.checking_account:
+            raise ValueError("User has no checking account")
+            
+        if other_user.balance < amount:
+            raise ValueError("Not enough money")
+            
+        other_user.balance -= amount
+        self.balance += amount
+        
+        return f"{self.name} has {self.balance} and {other_user.name} has {other_user.balance}."