docs: def add_term(self,term_obj):
          """
          Adds a term to the term layer
          @type term_obj: L{Cterm}
          @param term_obj: the term object
          """
          if self.term_layer is None:
              self.term_layer = Cterms(type=self.type)
              self.root.append(self.term_layer.get_node())
          self.term_layer.add_term(term_obj)