setAppearance(dict) {
    this.appearance = null;

    const appearanceStates = dict.get("AP");
    if (!(appearanceStates instanceof Dict)) {
      return;
    }

    // In case the normal appearance is a stream, then it is used directly.
    const normalAppearanceState = appearanceStates.get("N");
    if (normalAppearanceState instanceof BaseStream) {
      this.appearance = normalAppearanceState;
      return;
    }
    if (!(normalAppearanceState instanceof Dict)) {
      return;
    }

    // In case the normal appearance is a dictionary, the `AS` entry provides
    // the key of the stream in this dictionary.
    const as = dict.get("AS");
    if (!(as instanceof Name) || !normalAppearanceState.has(as.name)) {
      return;
    }
    const appearance = normalAppearanceState.get(as.name);
    if (appearance instanceof BaseStream) {
      this.appearance = appearance;
    }
  }
Set the (normal) appearance.

@public
@memberof Annotation
@param {Dict} dict - The annotation's data dictionary