def protect! password = ''
      @protected = true
      password = password.to_s
      if password.size == 0
        @password_hash = 0
      else
        @password_hash = Excel::Password.password_hash password
      end
    end
def protect! password = ''
      @protected = true
      password = password.to_s
      if password.size == 0
        @password_hash = 0
      else
        @password_hash = Excel::Password.password_hash password
      end
    end
Set worklist protection