code: def add_concept(self, concept_obj):
          ''' Add a concept to current concept list '''
          if concept_obj is None:
              raise Exception("Concept object cannot be None")
          elif concept_obj in self.__concepts:
              raise Exception("Concept object is already inside")
          elif concept_obj.cidx in self.__concept_map:
              raise Exception("Duplicated concept ID ({})".format(concept_obj.cidx))
          self.__concepts.append(concept_obj)
          self.__concept_map[concept_obj.cidx] = concept_obj
          concept_obj.sent = self
          return concept_obf add_concept(self, concept_obj):
          ''' Add a concept to current concept list '''
          if concept_obj is None:
              raise Exception("Concept object cannot be None")
          elif concept_obj in self.__concepts:
              raise Exception("Concept object is already inside")
          elif concept_obj.cidx in self.__concept_map:
              raise Exception("Duplicated concept ID ({})".format(concept_obj.cidx))
          self.__concepts.append(concept_obj)
          self.__concept_map[concept_obj.cidx] = concept_obj
          concept_obj.sent = self
          return concept_obj
docs: Add a concept to current concept list