优化嵌套的If语句和条件

def calculate_price(quantity):
    if quantity <= 0:
        return 0
    if quantity < 10:
        return quantity * 10
    if quantity < 100:
        return quantity * 8
    return quantity * 5

def is_valid_user(age, is_verified):
    if age >= 18 and is_verified:
        return True
    return False

def process_data(data_type, data):
    handlers = {
        'type1': handle_type1,
        'type2': handle_type2,
        'type3': handle_type3
    }
    if data_type in handlers:
        return handlers[data_type](data)
    else:
        return default_handler(data)