initial commit

banking.py

@@ -0,0 +1,37 @@
+from notification_service import send_notification
+
+
+class BankAccount:
+    def __init__(self, owner, balance=0):
+        if not owner.strip():
+            raise ValueError("Owner is required")
+        if balance < 0:
+            raise ValueError("Initial balance cannot be negative")
+        self.owner = owner
+        self.balance = balance
+
+    def deposit(self, amount):
+        if amount <= 0:
+            raise ValueError("Deposit must be positive")
+        self.balance += amount
+        return self.balance
+
+    def withdraw(self, amount):
+        if amount <= 0:
+            raise ValueError("Withdrawal must be positive")
+        if amount > self.balance:
+            raise ValueError("Insufficient funds")
+        self.balance -= amount
+        return self.balance
+
+    def transfer(self, recipient, amount):
+        if recipient is self:
+            raise ValueError("Cannot transfer to the same account")
+        if amount <= 0:
+            raise ValueError("Transfer must be positive")
+        if amount > self.balance:
+            raise ValueError("Insufficient funds")
+        self.balance -= amount
+        recipient.balance += amount
+        send_notification(recipient.owner, f"Received {amount} from {self.owner}")
+        return self.balance