message: can add a subsequence to a part
diff: @@ -4,6 +4,7 @@ import { atTime, Offline } from "test/helper/Offline";
  import { Time } from "Tone/core/type/Time";
  import { noOp } from "Tone/core/util/Interface";
  import { Part } from "./Part";
  +import { Sequence } from "./Sequence";
  import { ToneEvent } from "./ToneEvent";
  describe("Part", () => {
  @@ -175,6 +176,20 @@ describe("Part", () => {
  });
  });
  + it("can add a sequence", () => {
  + return Offline(() => {
  + const part = new Part();
  + expect(part.length).to.equal(0);
  + const subPart = new Sequence({
  + events: [0, 1, 2, 3],
  + });
  + part.add(0.2, subPart);
  + expect(part.length).to.equal(1);
  + expect(part.at(0.2)).to.equal(subPart);
  + part.dispose();
  + });
  + });
  +
  it("can remove an event by time", () => {
  return Offline(() => {
  const part = new Part({
  