def page(number)
      number = (n = number.to_i) > 0 ? n : 1
      Page.new(self, number, lambda {
                 offset = (number - 1) * @per_page
                 args = [offset]
                 args << @per_page if @select.arity == 2
                 @select.call(*args)
               })
    end
def page(number)
      number = (n = number.to_i) > 0 ? n : 1
      Page.new(self, number, lambda {
                 offset = (number - 1) * @per_page
                 args = [offset]
                 args << @per_page if @select.arity == 2
                 @select.call(*args)
               })
    end
Retrieve page object by number