docstr: generate fake sequence indexes with given length
docstr_tok: ["generate","fake","sequence","indexes","with","given","length"]
code: def gen_seq(self, length, vocab_size):
      """generate fake sequence indexes with given length"""
      # reserve 0 for padding
      return [randrange(1, vocab_size) for _ in range(length)]
  
file_path: fastNLP/tests/models/torch/model_runner.py
imports: from fastNLP.envs.imports import _NEED_IMPORT_TORCH
  from fastNLP import Trainer, Evaluator, DataSet, Callback
  from fastNLP import Accuracy
  from random import randrange
  from fastNLP import TorchDataLoader
label_desc: Use image node_id 1 for calling the ModelRunner obj's underlying member method code with example usage: obj.gen_seq(length, vocab_size) and returns: unknown