[
    :unit,
    [
        :task_def,
        "Simple",
        [
            :task_signature,
            [
                :fluent,
                "diagKnown",
                [
                    :event_set,
                    "Diagnosis:start"
                ],
                [
                    :event_set,
                    "Treatment:end"
                ],
                nil
            ]
        ],
        [
            :task_refinement,
            [
                :seq_st,
                [
                    :if_st,
                    [
                        :bool_not,
                        [
                            :var_ref,
                            "diagKnown"
                        ]
                    ],
                    [
                        :task_call_st,
                        "Diagnosis"
                    ],
                    [
                        :else_clause,
                        [
                            :task_call_st,
                            "NoDiag"
                        ]
                    ]
                ],
                [
                    :task_call_st,
                    "Treatment"
                ]
            ]
        ]
    ]
]