def parameters(val = NULL)
      if null?(val)
        @parameters || {}
      else
        unless val.is_a?(Hash)
          raise InvalidValue.new(:parameters, "be a Hash")
        end

        @parameters = val
      end
    end
def parameters(val = NULL)
      if null?(val)
        @parameters || {}
      else
        unless val.is_a?(Hash)
          raise InvalidValue.new(:parameters, "be a Hash")
        end

        @parameters = val
      end
    end
Set or retrieve the custom msi building parameters.

 @example
   parameters {
     'MagicParam' => 'ABCD-1234'
   }

 @param [Hash] val
   the parameters to set

 @return [Hash]
   the set parameters