@typecheck_method(start=IR, stop=IR, step=IR)
def copy(self, start, stop, step):
    new_instance = self.__class__
    return new_instance(start, stop, step)
@typecheck_method(start=IR, stop=IR, step=IR)
def copy(self, start, stop, step):
    new_instance = self.__class__
    return new_instance(start, stop, step)