          "r1": 1164.9333333333334,
              "depth": 7,
              "children": 1
            },
            {
              "args": [
                {
                  "coins-inserted": ["quarter"],
                  "coins-returned": [],
                  "dispensed": null,
                  "inventory": { "a1": { "name": "taco", "qty": 10, "price": 0.85 } },
                  "err-msg": null
                },
                "dime"
              ],
              "parent": "root",
             