input: Write a python function to create a BankAccount class with methods to deposit, withdraw, and check balance.
  assert bank.get_balance() == 1000
  assert bank.deposit(500) == 1500
  assert bank.withdraw(300) == 1200
output: class BankAccount:
      def __init__(self, initial_balance=0):
          self.balance = initial_balance
      
      def deposit(self, amount):
          self.balance += amount
          return self.balance
      
      def withdraw(self, amount):
          if amount > self.balance:
              raise ValueError("Insufficient funds")
          self.balance -= amount
          return self.balance
      
      def get_balance(self):
          return self.balance
  
  # Example usage:
  bank = BankAccount(1000)