docs: def create_term(self, lemma, pos, morphofeat, tokens, id=None):
          """
          Create a new term and add it to the term layer
          @type lemma: string
          @param lemma: The lemma of the term
          @type pos: string
          @param pos: The postrag(rst letter) of the POS attribute
          @type morphofeat: string
          @param morphofeat: The morphofeat (full morphological features) of the term
          @type tokens: sequence of L{Cwf}
          @param tokens: the token(s) that this term describes
          @type id: string
          @param id: the id of the term, if not given an id tXXX will be created
          """
          if id is None:
              n = 1 if self.term_layer is None else len(self.term_layer.idx) + 1
              id = "t{n}".format(**locals())
          new_term = Cterm(type=self.type)
          new_term.set_id(id)
          new_term.set_lemma(lemma)
          new_term.set_pos(pos)
          new_term.set_morphofeat(morphofeat)
          new_span = Cspan()
          for token in tokens:
              new_span.add_target_id(token.get_id())
          new_term.set_span(new_span)
          self.add_term(new_term)
          return new_term