我正在创建一个非常简单的Calculator类，并且我想创建一个能够独立工作的减法方法，或者至少在类本身指定的方法中。
问题是，对于减法，如果我使用-=，就像我使用+=进行加法一样，它将无法正常工作，并给予第一个数字减去起始值0。
该方法接受 *args，所以我可以给予任意多的数字，我现在试图使它接受第一个参数/数字作为默认值，然后减去其他数字的总和（使用我自己的加法方法）。
这是我到现在为止得到的代码：

class Calculator:
    """An attempt to create a calculator."""

    def __init__(self):
        self.current_value = 0

    # type hinting stuff:
    # https://stackoverflow.com/questions/50928592/mypy-type-hint-unionfloat-int-is-there-a-number-type
    def add(self, *args: float, reset=False):
        """
        Takes in a series of numbers as iterable and sums them up.

        If the iterable is empty, or has only one value, the function is invalid.

        :param args: Creates an iterable of any number. Can be `int` or `float`.
        :param reset: A boolean flag. If set to True, resets the current value to 0.
        :return: Return the sum of the 'start' value (default: 0) plus an iterable of numbers.
        """

        if reset:
            self.current_value = 0

        if len(args) >= 1:
            total = self.current_value
            for num in args:
                if isinstance(num, (int, float)):
                    total += num
                else:
                    print(f"Insert only valid numbers (integers or floats).  Try again...")

            self.current_value = total
            return total

        else:
            print(f"Insert at least one valid number (integer or float). Try again...")

    def subtract(self, *args: float, reset=True):
        """
        Takes in a series of numbers as iterable and subtracts them to the starting value of the first number.

        If the iterable is empty, the function returns 0.

        :param args: Creates an iterable of any number. Can be `int` or `float`.
        :param reset: A boolean flag. If set to True, resets the current value to 0.
        :return: Return the subtraction of the values inputted as iterables.
        """

        if reset:
            self.current_value = 0

        if len(args) >= 1:

            for num in args:
                if isinstance(num, (int, float)):
                    arg += num
                    continue
                else:
                    print(f"Insert only valid numbers (floats or integers). Try again...")
                    return None

            print(f'Current value: {self.current_value}')
            print(f'Sum of args', self.add(args))

            total = self.current_value - self.add(args)

            self.current_value = total
            return total

        else:
            print(f"Insert at least one valid number (integer or float). Try again...")

当前值用于保留先前操作的内存。因此，例如，如果我添加（5，2）= 7，然后调用subtract（3），它将是= 4，因为计算器的内存中存储了7，直到我手动重置它。