How to use the attrs.Attr function in attrs

class ToggleButton(BasicTextWidget):
	"""
	A basic push button that can be toggled.

	Unfortunately a bit of code duplication from ImageButton.

	New Attributes
	==============

	  - group: String: The group the button belongs to. Only one button in each group will be toggled at one time.
	  - toggled: Boolean: Whether the button is toggled or not.
	"""

	ATTRIBUTES = BasicTextWidget.ATTRIBUTES + [
		Attr('up_image'),Attr('down_image'),Attr('hover_image'),
		PointAttr('offset'),Attr('group')
	]

	def __init__(self,up_image="",down_image="",hover_image="",offset=(0,0),group="",**kwargs):

		self.real_widget = fife.ToggleButton()
		super(ToggleButton,self).__init__(**kwargs)
		self.group = group
		self.up_image = up_image
		self.down_image = down_image
		self.hover_image = hover_image
		self.offset = offset

	def _setGroup(self,group):
		self.real_widget.setGroup( group )

text = property(_getText,_setText)

	def resizeToContent(self, recurse = True):
		self.height = self.real_font.getHeight() + self.margins[1]*2
		self.width = self.real_font.getWidth(_text2gui(self.text)) + self.margins[0]*2

class Icon(Widget):
	"""
	An image icon.

	New Attributes
	==============

	  - image: String or GuiImage: The source location of the Image or a direct GuiImage
	"""
	ATTRIBUTES = Widget.ATTRIBUTES + [Attr('image')]

	def __init__(self,image="",**kwargs):
		self.real_widget = fife.Icon(None)
		super(Icon,self).__init__(**kwargs)
		self._source = self._image = None
		if image:
			self.image = image

	def _setImage(self,source):
		if isinstance(source,str):
			self._source = source
			self._image = get_manager().loadImage(source)
		elif isinstance(source,fife.GuiImage):
			self._source = None
			self._image = source
		else:

class TextBox(Widget):
	"""
	An editable B{multiline} text edit widget.

	New Attributes
	==============

	  - text: The text in the TextBox.
	  - filename: A write-only attribute - assigning a filename will cause the widget to load it's text from it.

	Data
	====
	The text can be read and set via L{distributeData} and L{collectData}.
	"""

	ATTRIBUTES = Widget.ATTRIBUTES + [UnicodeAttr('text'),Attr('filename')]

	def __init__(self,text=u"",filename = "", **kwargs):
		self.real_widget = fife.TextBox()
		self.text = text
		self.filename = filename
		super(TextBox,self).__init__(**kwargs)

		# Prepare Data collection framework
		self.accepts_data = True
		self.accepts_initial_data = True # Make sense in a way ...
		self._realSetInitialData = self._setText
		self._realSetData = self._setText
		self._realGetData = self._getText

	def _getFileName(self): return self._filename
	def _loadFromFile(self,filename):