@java.lang.Override
  public com.google.cloud.texttospeech.v1.CustomVoiceParams getCustomVoice() {
    return customVoice_ == null
        ? com.google.cloud.texttospeech.v1.CustomVoiceParams.getDefaultInstance()
        : customVoice_;
  }
<pre>
The configuration for a custom voice. If [CustomVoiceParams.model] is set,
the service will choose the custom voice matching the specified
configuration.
</pre>

<code>.google.cloud.texttospeech.v1.CustomVoiceParams custom_voice = 4;</code>

@return The customVoice.
java-texttospeech/proto-google-cloud-texttospeech-v1/src/main/java/com/google/cloud/texttospeech/v1/VoiceSelectionParams.java