def METHOD_NAME(amount, number):
    """Multiply the given amount by a number.
    Args:
      amount: An instance of Amount.
      number: A decimal number.
    Returns:
      An Amount, with the same currency, but with 'number' times units.
    """
    assert isinstance(amount.number, Decimal), (
        "Amount's number is not a Decimal instance: {}".format(amount.number))
    assert isinstance(number, Decimal), (
        "Number is not a Decimal instance: {}".format(number))
    return Amount(amount.number * number, amount.currency)