code: def test_save_inference_model(self):
      self.module.save_inference_model("./inference/model")
  
      self.assertTrue(
          os.path.exists("./inference/model/angle_classifier.pdmodel")
      )
      self.assertTrue(
          os.path.exists("./inference/model/angle_classifier.pdiparams")
      )
  
      self.assertTrue(
          os.path.exists("./inference/model/text_detector.pdmodel")
      )
      self.assertTrue(
          os.path.exists("./inference/model/text_detector.pdiparams")
      )
  
      self.assertTrue(
          os.path.exists("./inference/model/text_recognizer.pdmodel")
      )
      self.assertTrue(
          os.path.exists("./inference/model/text_recognizer.pdiparams")
      )
  
file_path: PaddleHub/modules/image/text_recognition/chinese_ocr_db_crnn_server/test.py
imports: import os
  import shutil
  import unittest
  import cv2
  import requests
  import paddlehub
label_desc: Use image node_id 9 for calling the TestHubModule obj's underlying member method code with example usage: obj.test_save_inference_model() without return types