__init__ & Instance Attributes

class BankAccount:
    def __init__(self, owner, balance=0):
        self.owner = owner
        self.balance = balance
        self.transactions = []
    
    def deposit(self, amount):
        if amount > 0:
            self.balance += amount
            self.transactions.append(f"+{amount}")
            print(f"Deposited: {amount}. Balance: {self.balance}")
    
    def withdraw(self, amount):
        if 0 < amount <= self.balance:
            self.balance -= amount
            self.transactions.append(f"-{amount}")
            print(f"Withdrawn: {amount}. Balance: {self.balance}")
        else:
            print("Insufficient funds!")
    
    def summary(self):
        print(f"\n=== {self.owner}'s Account ===")
        print(f"Balance: ${self.balance}")
        print(f"Transactions: {', '.join(self.transactions)}")

# Usage
acc = BankAccount("Alice", 1000)
acc.deposit(500)
acc.withdraw(200)
acc.withdraw(2000)
acc.summary()