def _order_steps(self):
        steps = list(copy.copy(self.default_steps))
        additional = self._registry.keys()
        for step in additional:
            try:
                min_pos = steps.index(step.after)
            except __HOLE__:
                min_pos = 0
            try:
                max_pos = steps.index(step.before)
            except ValueError:
                max_pos = len(steps)
            if min_pos > max_pos:
                raise exceptions.WorkflowError("The step %(new)s can't be "
                                               "placed between the steps "
                                               "%(after)s and %(before)s; the "
                                               "step %(before)s comes before "
                                               "%(after)s."
                                               % {"new": additional,
                                                  "after": step.after,
                                                  "before": step.before})
            steps.insert(max_pos, step)
        return steps
dataset/ETHPy150Open Havate/havate-openstack/proto-build/gui/horizon/Horizon_GUI/horizon/workflows/base.py/Workflow._order_steps