constructor(containers = [], options = {}) {
    super(containers, {
      ...options,
      announcements: {
        ...defaultAnnouncements,
        ...(options.announcements || {}),
      },
    });

    /**
     * Last draggable element that was dragged over
     * @property lastOver
     * @type {HTMLElement}
     */
    this.lastOver = null;

    this[onDragStart] = this[onDragStart].bind(this);
    this[onDragOver] = this[onDragOver].bind(this);
    this[onDragStop] = this[onDragStop].bind(this);

    this.on('drag:start', this[onDragStart])
      .on('drag:over', this[onDragOver])
      .on('drag:stop', this[onDragStop]);
  }
Swappable constructor.
@constructs Swappable
@param {HTMLElement[]|NodeList|HTMLElement} containers - Swappable containers
@param {Object} options - Options for Swappable