message: no need to guard against the part being undefined now
diff: @@ -231,10 +231,8 @@ export class Sequence<ValueType = any> extends ToneEvent<ValueType> {
  return this._part.loop;
  }
  set loop(l) {
  - if (this._part) {
  this._part.loop = l;
  }
  - }
  /**
  * The index at which the sequence should start looping
  @@ -244,10 +242,8 @@ export class Sequence<ValueType = any> extends ToneEvent<ValueType> {
  }
  set loopStart(index) {
  this._loopStart = index;
  - if (this._part) {
  this._part.loopStart = this._indexTime(index);
  }
  - }
  /**
  * The index at which the sequence should end looping
  @@ -257,50 +253,40 @@ export class Sequence<ValueType = any> extends ToneEvent<ValueType> {
  }
  set loopEnd(index) {
  this._loopEnd = index;
  - if (this._part) {
  if (index === 0) {
  this._part.loopEnd = this._indexTime(this._eventsArray.length);
  } else {
  this._part.loopEnd = this._indexTime(index);
  }
  }
  - }
  get startOffset(): Ticks {
  return this._part.startOffset;
  }
  set startOffset(start) {
  - if (this._part) {
  this._part.startOffset = start;
  }
  - }
  get playbackRate(): Positive {
  return this._part.playbackRate;
  }
  set playbackRate(rate) {
  - if (this._part) {
  this._part.playbackRate = rate;
  }
  - }
  get probability(): NormalRange {
  return this._part.probability;
  }
  set probability(prob) {
  - if (this._part) {
  this._part.probability = prob;
  }
  - }
  get humanize(): boolean | Time {
  return this._part.humanize;
  }
  set humanize(variation) {
  - if (this._part) {
  this._part.humanize = variation;
  }
  - }
  /**
  * The number of scheduled events
  