code: def add_model_file(self, model_fpath, position=1, file_id=None):
          
          if file_id is None:
              file_id = self.make_unique_id('file_input')
          ret_data = self.file_create(File.from_file(model_fpath, position,
                                                     file_id))
          return ret_data
docs: Add a kappa model from a file at given path to the project.