code: func (o *copier) Cleanup() {
  	for _, path := range o.tmpPaths {
  		os.RemoveAll(path)
  	}
  	o.tmpPaths = []string{}
  	if o.activeLayer != nil {
  		o.activeLayer.Release()
  		o.activeLayer = nil
  	}
  }
docs: // Cleanup removes any temporary directories created as part of downloading
  // remote files.