code: def testExists(self):
      temp_dir = self._CreateDeepS3Structure()
      ckpt_path = self._PathJoin(temp_dir, "model.ckpt")
      self.assertTrue(gfile.exists(temp_dir))
      self.assertTrue(gfile.exists(ckpt_path))
  
imports: import boto3
  import os
  import unittest
  from moto import mock_s3
  from tensorboard.compat.tensorflow_stub import errors
  from tensorboard.compat.tensorflow_stub.io import gfile
label_desc: Use image node_id 1 for calling the GFileTest obj's underlying member method code with example usage: obj.testExists() without return types