toJson method 
    
    
    
  Implementation
  core.Map<core.String, core.dynamic> toJson() => {
  if (args != null) 'args': args!,
  if (enableWebAccess != null) 'enableWebAccess': enableWebAccess!,
  if (encryptionConfig != null) 'encryptionConfig': encryptionConfig!,
  if (evaluatorConfig != null) 'evaluatorConfig': evaluatorConfig!,
  if (evaluatorCount != null) 'evaluatorCount': evaluatorCount!,
  if (evaluatorType != null) 'evaluatorType': evaluatorType!,
  if (hyperparameters != null) 'hyperparameters': hyperparameters!,
  if (jobDir != null) 'jobDir': jobDir!,
  if (masterConfig != null) 'masterConfig': masterConfig!,
  if (masterType != null) 'masterType': masterType!,
  if (network != null) 'network': network!,
  if (packageUris != null) 'packageUris': packageUris!,
  if (parameterServerConfig != null)
    'parameterServerConfig': parameterServerConfig!,
  if (parameterServerCount != null)
    'parameterServerCount': parameterServerCount!,
  if (parameterServerType != null)
    'parameterServerType': parameterServerType!,
  if (pythonModule != null) 'pythonModule': pythonModule!,
  if (pythonVersion != null) 'pythonVersion': pythonVersion!,
  if (region != null) 'region': region!,
  if (runtimeVersion != null) 'runtimeVersion': runtimeVersion!,
  if (scaleTier != null) 'scaleTier': scaleTier!,
  if (scheduling != null) 'scheduling': scheduling!,
  if (serviceAccount != null) 'serviceAccount': serviceAccount!,
  if (useChiefInTfConfig != null) 'useChiefInTfConfig': useChiefInTfConfig!,
  if (workerConfig != null) 'workerConfig': workerConfig!,
  if (workerCount != null) 'workerCount': workerCount!,
  if (workerType != null) 'workerType': workerType!,
};