# File xmlconfigfile.rb, line 89
  def set_parameter(xpath, value, create = false)
    parameter = XPath.first(@doc, xpath)
    if parameter.nil?
      if create
        raise ArgumentError, "Not yet implemented!"
      else
        raise ArgumentError
      end
      raise ArgumentError
    elsif parameter.instance_of?(Element)
      parameter.text = value.to_s
    elsif parameter.instance_of?(Attribute)
      parameter.element.add_attribute(parameter.name, value.to_s)
    end
    changed
    notify_observers(@filename)
  end