Unpacking args to list not working

Here is my code. I cannot for the life of me find out why it's not unpacking the *args to a list argslist. When I print the argslist immediately after that, it only reads '1'. This is the first time I've worked with *args. I've looked over the Python documentation and several articles and still don't understand why this isn't working.

def checkio(*args):
    args_list = list(range(*args))
    print (args_list)
    nums = []
    for item in args_list:
        nums.append(float(item))
    nums.sort()
    diff = abs(nums[-1] - nums[0])
    return diff