# File lib/blimpy/fleet.rb, line 21
    def add(box_type, &block)
      unless valid_types.include? box_type
        raise Blimpy::InvalidShipException
      end
      if block.nil?
        return false
      end

      box = nil
      if box_type == :aws
        box = Blimpy::Boxes::AWS.new
      end
      if box_type == :openstack
        box = Blimpy::Boxes::OpenStack.new
      end

      if box.nil?
        return false
      end
      box.fleet_id = @id
      @ships << box
      block.call(box)
    end