Flint

contract Bank {
  var balances: [Address: Int] = [:]
  var owner: Address

  init(owner: Address) {
    self.owner = owner
  }

  public mutating func deposit(implicit value: inout Wei) {
    balances[caller] = balances[caller] + value.transfer(&value)
  }

  public mutating func withdraw(amount: Int) {
    balances[caller] = balances[caller] - amount
    send(caller, amount)
  }

  public func getBalance() -> Int {
    return balances[caller]
  }
}