Stuck with error in prewritten code

Here's my code:

def checkio(*args): if args:

   return (max(args) - min(args))

else:

    return '0'

And I am getting the error:

TypeError: '<' not supported between instances of 'float' and 'str' almost_equal, 11 <module>, 16

Does this mean there is an error in the self-checking code?