SInatra，续集分页

Question

我遇到了分页问题。除了要求续集和sinatra我还有：

require 'will_paginate'
require 'sequel/extensions/pagination'
require 'will_paginate/collection'
require 'will_paginate/sequel'
require 'will_paginate/version'

查询是：

get '/candidate' do
      @items = DB[:candidates].order(:created_at).paginate(params[:page], 10)
     erb :candidate
end

并且candidate.erb上的错误消息是：

undefined method `-' for nil:NilClass

    file: pagination.rb
    location: paginate
    line: 19

可能是什么问题？查询好吗？感谢所有的帮助。