{"action": "use", "length": [""], "output": ""}
{"action": "define", "container": ["the sub"], "device": ["", ""], "output": "", "reagent": ["", ""]}
{"action": "use", "device": [""], "output": ""}
{"action": "define", "length": ["second-level sub-steps", "third[[-]]level sub-[[steps]]"], "output": ""}
{"action": "use", "length": [""], "output": ""}
{"action": "define", "container": ["the sub"], "device": ["", ""], "output": "", "reagent": ["", ""]}