- ensure_user_exists(username)
- self.bank['username']['balance'][0] += amount[0]
- self.bank['username']['balance'][1] += amount[1]
+ self.ensure_user_exists(username)
+ (cur_cents, cur_bytes) = self.bank[username]['balance']
+ (add_cents, add_bytes) = amount
+ self.bank[username]['balance'] = (cur_cents+add_cents,
+ cur_bytes+add_bytes)