# File lib/sinatra/rabbit.rb, line 297
      def collection(name, opts={}, &block)
        if subcollections.keys.include?(name)
          raise DuplicateOperationException::new(500, "DuplicateSubcollection", "Subcollection #{name} is already defined", [])
        end
        subcollections[name] = SubCollection.new(self, name, opts, &block)
        subcollections[name].generate
      end