code: def test_empty(self, device_spec_type):
      d = device_spec_type()
      self.assertEqual("", d.to_string())
      d.parse_from_string("")
      self.assertEqual("", d.to_string())
  
file_path: tensorflow-upstream/tensorflow/python/framework/device_spec_test.py
imports: from absl.testing import parameterized
  from tensorflow.python.framework import device_spec
  from tensorflow.python.framework import test_util
  from tensorflow.python.platform import googletest
label_desc: Use image node_id 1 for calling the DeviceSpecTest obj's underlying member method code with example usage: obj.test_empty(device_spec_type) without return types