input: Write a function to simulate a simple ATM machine using the provided classes and methods. The function should take user commands to create accounts, deposit money, withdraw money, and check account balances based on the given format. If no accounts are created, the function should handle that scenario appropriately.
  assert simple_atm([])==None
  assert simple_atm(["create_account John 100", "deposit John 50", "print_balance John"])==None
  assert simple_atm(["create_account Jane 50", "withdrawal Jane 20", "print_balance Jane"])==None
  assert simple_atm(["create_account Tony 200", "withdrawal Tony 300", "print_balance Tony"])==None
output: def simple_atm(commands):
      accounts = {}
      for command in commands:
          parts = command.split()
          action = parts[0]
          if action == "create_account":
              name = parts[1]
              balance = int(parts[2])
              accounts[name] = balance
          elif action == "deposit":
              name = parts[1]
              amount = int(parts[2])
              if name in accounts:
                  accounts[name] += amount
          elif action == "withdrawal":
              name = parts[1]
              amount = int(parts[2])
              if name in accounts:
                  if accounts[name] >= amount:
                      accounts[name] -= amount
          elif action == "print_balance":
              name = parts[1]
              if name in accounts:
                  print(accounts[name])