code: func NewExecMounter(exec mount.Exec, wrapped mount.Interface) mount.Interface {
  	return &execMounter{
  		wrappedMounter: wrapped,
  		exec:           exec,
  	}
  }
docs: // NewExecMounter returns a mounter that uses provided Exec interface to mount and
  // unmount a filesystem. For all other calls it uses a wrapped mounter.