How to use the merlin.study.step.Step function in merlin

def test_get_task_queue_default():
    """
    Given a steps dictionary that sets the task queue to `test_queue` return
    `test_queue` as the queue name.
    """
    steps = {"run": {"task_queue": "test_queue"}}
    queue = Step.get_task_queue_from_dict(steps)
    assert queue == "test_queue"

def test_get_task_queue_run_missing():
    """
    Given an empty steps dictionary return `merlin` as the queue name.
    """
    steps = {}
    queue = Step.get_task_queue_from_dict(steps)
    assert queue == "merlin"

def step(self, task_name):
        """Return a Step object for the given task name

        :param `task_name`: The task name.
        :return: A Merlin Step object.
        """
        return Step(self.dag.values[task_name])

step_dict["run"]["cmd"] = re.sub(re.escape(str1), str2, cmd, flags=re.I)

                restart_cmd = step_dict["run"]["restart"]
                if restart_cmd:
                    step_dict["run"]["restart"] = re.sub(
                        re.escape(str1), str2, restart_cmd, flags=re.I
                    )

        if new_workspace is None:
            new_workspace = self.get_workspace()
        LOG.debug(f"cloned step with workspace {new_workspace}")
        study_step = StudyStep()
        study_step.name = step_dict["name"]
        study_step.description = step_dict["description"]
        study_step.run = step_dict["run"]
        return Step(_StepRecord(new_workspace, study_step))