def process(items):
    result = []
    for i, item in enumerate(items):
        if item > 0:
            result.append(item * 2)
        elif item < 0:
            result.append(-item)
        else:
            pass
    total = sum(result)
    return total

class Calculator:
    def __init__(self, base=10):
        self.base = base

    def add(self, x, y):
        return x + y

    def multiply(self, x, y):
        return x * y

x = process([1, -2, 0])
calc = Calculator()
sum_result = calc.add(5, 15)