functions.py

def multiply_numbers(a, b):
    return a * b


def reverse_list(input_list):
    return input_list[::-1]


def calculate_discount(price, discount_percentage):
    if not (0 <= discount_percentage <= 100):
        raise ValueError("Discount percentage must be between 0 and 100")
    return price * (1 - discount_percentage / 100)


class MathOperations:
    def is_prime(self, n):
        if n <= 1:
            return False
        if n <= 3:
            return True
        if n % 2 == 0 or n % 3 == 0:
            return False
        i = 5
        while i * i <= n:
            if n % i == 0 or n % (i + 2) == 0:
                return False
            i += 6
        return True

    def factorial(self, n):
        if n < 0:
            raise ValueError("Factorial not defined for negative numbers")
        if n == 0:
            return 1
        result = 1
        for i in range(1, n + 1):
            result *= i
        return result