human
I wrote the below code

    class RequiredLength(Action, ):
        def __call__(self, parser, args, values, option_string=None):
            if (not (nmin <= len(values) <= nmax)):
                raise ArgumentError(self, (u'requires    between    %s    and    %s    arguments' % (nmin, nmax)))
            setattr(args, self.dest, values)
    return RequiredLength

What's a good function header?

=====
Here's a good function header?
assistant
#Here's a good function header.

def required_length(nmin, nmax):