public Builder clearModel() {
      model_ = getDefaultInstance().getModel();
      bitField0_ = (bitField0_ & ~0x00000020);
      onChanged();
      return this;
    }
<pre>
Optional. The `model` type requested for this translation.

The format depends on model type:

- AutoML Translation models:
  `projects/{project-number-or-id}/locations/{location-id}/models/{model-id}`

- General (built-in) models:
  `projects/{project-number-or-id}/locations/{location-id}/models/general/nmt`,


If not provided, the default Google model (NMT) will be used for
translation.
</pre>

<code>string model = 6 [(.google.api.field_behavior) = OPTIONAL];</code>

@return This builder for chaining.
java-translate/proto-google-cloud-translate-v3/src/main/java/com/google/cloud/translate/v3/TranslateDocumentRequest.java