Create a new (named) entity and add it to the entities layer
        @type entity_type: string
        @param entity_type: The type of the entity
        @type term_ids: list
        @param term_ids: list of term ids
        @type id: string
        @param id: optional id of the entity

def create_entity(self, entity_type, term_ids, id=None):
        """
        Create a new (named) entity and add it to the entities layer
        @type entity_type: string
        @param entity_type: The type of the entity
        @type term_ids: list
        @param term_ids: list of term ids
        @type id: string
        @param id: optional id of the entity
        """
        new_entity = Centity(type=self.type)
        if id is None:
            n = 1 if self.entity_layer is None else len(self.entity_layer.map_entity_id_to_node) + 1
            id = "e{n}".format(**locals())
        new_entity.set_id(id)
        new_entity.set_type(entity_type)
        references = Creferences()
        references.add_span(term_ids)
        new_entity.add_reference(references)
        self.add_entity(new_entity)
        return new_entity