unapply (handler) {
    super.unapply(handler, () => {
      let bChangedTransform = false
      Object.entries(this.oldValues).forEach(([attr, value]) => {
        if (value) {
          if (attr === '#text') {
            this.elem.textContent = value
          } else if (attr === '#href') {
            setHref(this.elem, value)
          } else {
            this.elem.setAttribute(attr, value)
          }
        } else if (attr === '#text') {
          this.elem.textContent = ''
        } else {
          this.elem.removeAttribute(attr)
        }
        if (attr === 'transform') { bChangedTransform = true }
      })
      // relocate rotational transform, if necessary
      if (!bChangedTransform) {
        const angle = getRotationAngle(this.elem)
        if (angle) {
          const bbox = getBBox(this.elem)
          const cx = bbox.x + bbox.width / 2
          const cy = bbox.y + bbox.height / 2
          const rotate = ['rotate(', angle, ' ', cx, ',', cy, ')'].join('')
          if (rotate !== this.elem.getAttribute('transform')) {
            this.elem.setAttribute('transform', rotate)
          }
        }
      }
    })
  }
Reverses the stored change action.
@param {module:history.HistoryEventHandler} handler
@fires module:history~Command#event:history
@returns {void}