code: def add_wf(self,wf_obj):
          
          if self.text_layer is None:
              self.text_layer = Ctext(type=self.type)
              self.root.append(self.text_layer.get_node())
          self.text_layer.add_wf(wf_obj)
docs: Adds a token to the text layer
          @type wf_obj: L{Cwf}
          @param wf_obj: the token object