relation_class_for

# File activerecord/lib/active_record/relation/delegation.rb, line 91
      def relation_class_for(klass)
        if klass && (klass_name = klass.name)
          my_cache = @@subclasses.compute_if_absent(self) { ThreadSafe::Cache.new }
          # This hash is keyed by klass.name to avoid memory leaks in development mode
          my_cache.compute_if_absent(klass_name) do
            # Cache#compute_if_absent guarantees that the block will only executed once for the given klass_name
            const_get("#{name.gsub('::', '_')}_#{klass_name.gsub('::', '_')}", false)
          end
        else
          ActiveRecord::Relation
        end
      end