'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.'

def get_next_step(self, step=None):

    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
