var c_metric = CompoundMetric.make({
    "name": "MyCMetric",
    "id": "MyCMetric",
    "expression": "MyExpression"
});

var c_spec = EvalMetricsSpec.make({
  ids: ["MyID"],
  expressions: ["MyCMetric"],
  start: "2015-01-01",
  end: "2019-06-01",
  interval: "DAY"
});

c3Viz(MyType.evalMetricsWithMetadata(c_spec,[c_metric]));