title: can't dump anonymous class #<Module -error on caching in rails 3
body: <p>I am getting can't dump anonymous class error.</p>
  
  <p>I have the following methods in my model. </p>
  
  <pre><code> def seating_for(active)
     ln = cache(col("lu", active)) do
      self.seat_list_for(active).where(seat_id: self.seat_entries)
   end
  
   def seat_list_for(active)
     ex_id = Exc.id_by_symbol(active)
     self.row.exe.seats.where(ex_id: exc_id).first.seat_alloc_mem
   end
  </code></pre>
  
  <p>I am trying to cache ln. I am getting an error. Can't figure out what is the problem.</p>
  
  <pre><code> can't dump anonymous class #&lt;Module:0x00000007ab6088&gt;
   /home/#/.rvm/gems/ruby-2.0.0-p0@anon-ui/gems/activesupport-3.2.14/lib/active_support/cache.rb:561:in `dump'
   /home/#/.rvm/gems/ruby-2.0.0-p0@anon-ui/gems/activesupport-3.2.14/lib/active_support/cache.rb:561:in `initialize'
   /home/#/.rvm/gems/ruby-2.0.0-p0@anon-ui/gems/redis-activesupport-3.2.4/lib/active_support/cache/redis_store.rb:34:in `new'
   /home/#/.rvm/gems/ruby-2.0.0-p0@anon-ui/gems/redis-activesupport-3.2.4/lib/active_support/cache/redis_store.rb:34:in `block in write'
   /home/#/.rvm/gems/ruby-2.0.0-p0@anon-ui/gems/activesupport-3.2.14/lib/active_support/cache.rb:520:in `instrument'
   /home/#/.rvm/gems/ruby-2.0.0-p0@anon-ui/gems/redis-activesupport-3.2.4/lib/active_support/cache/redis_store.rb:33:in `write'
   /home/#/.rvm/gems/ruby-2.0.0-p0@anon-ui/gems/activesupport-3.2.14/lib/active_support/cache.rb:299:in `fetch'
   /home/#/user/projects/app/#/lib/lib_utility.rb:15:in `cache'
   /home/#/user/projects/app/#/app/models/smthng.rb:566:in `seating_for'
  </code></pre>
  
  <p>lib/lib_utility.rb</p>
  
  <pre><code>module LibUtility
    module ClassMethods
      def col(p, l)
       //smthng
      end
  
     def cache(l, options={}, &amp;b)
       Rails.cache.fetch(l, expires_in: 50.minutes, &amp;b)
     end
    end
  
    def self.included(receiver)
      receiver.extend ClassMethods
    end
  
  end
  </code></pre>
  
  <p>Needs guidance??</p>