code: def get_next_step(self, step=None):
          
          if step is None:
              step = self.steps.current
          form_list = self.get_form_list()
          keys = list(form_list.keys())
          key = keys.index(step) + 1
          for next_step in keys[key:]:
              if self.is_step_visible(next_step):
                  return next_step
          return None
docs: 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.