def greater_than(stack):
    """
    Take the stack, pop off four items, if the first conditional is larger than
    the second conditional append the first item to the stack, otherwise,
    append the second.
    """
    item_1 = stack.pop()
    item_2 = stack.pop()
    conditional_1 = stack.pop()
    conditional_2 = stack.pop()
    if conditional_1 > conditional_2:
        stack.append(item_1)
    else:
        stack.append(item_2)
