def get_next_step(self, step=None):
        """
        Returns the next step after the given `step`. If no more steps are
        available, None will be returned. If the `step` argument is None, the
        current step will be determined automatically.
        """
        if step is None:
            step = self.steps.current
        form_list = self.get_form_list()
        key = form_list.keyOrder.index(step) + 1
        if len(form_list.keyOrder) > key:
            return form_list.keyOrder[key]
        return None