code: def new_concept(self, tag, clemma="", tokens=None, cidx=None, **kwargs):
          ''' Create a new concept object and add it to concept list
          tokens can be a list of Token objects or token indices
          '''
          if cidx is None:
              cidx = self.new_concept_id()
          if tokens:
              tokens = (t if isinstance(t, Token) else self[t] for t in tokens)
          c = Concept(cidx=cidx, tag=tag, clemma=clemma, sent=self, tokens=tokens, **kwargs)
          return self.add_concept(cf new_concept(self, tag, clemma="", tokens=None, cidx=None, **kwargs):
          ''' Create a new concept object and add it to concept list
          tokens can be a list of Token objects or token indices
          '''
          if cidx is None:
              cidx = self.new_concept_id()
          if tokens:
              tokens = (t if isinstance(t, Token) else self[t] for t in tokens)
          c = Concept(cidx=cidx, tag=tag, clemma=clemma, sent=self, tokens=tokens, **kwargs)
          return self.add_concept(c)
docs: Create a new concept object and add it to concept list
          tokens can be a list of Token objects or token indices