Design a class for a simple calculator.
user
class Calculator:
    def __init__(self):
        self.result = 0

    def add(self, value):
        self.result += value

    def subtract(self, value):
        self.result -= value

    def multiply(self, value):
        self.result *= value

    def divide(self, value):
        self.result /= value

    def get_result(self):
        return self.result
assistant