code: def testEmpty(self):
      hparams = hparam.HParams()
      self.assertDictEqual({}, hparams.values())
      hparams.parse("")
      self.assertDictEqual({}, hparams.values())
      with self.assertRaisesRegexp(
          ValueError, "Unknown hyperparameter"
      ):
          hparams.parse("xyz=123")
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from tensor2tensor.utils import hparam
  import tensorflow.compat.v1
label_desc: Use image node_id 1 for calling the HParamsTest obj's underlying member method code with example usage: obj.testEmpty() without return types