public static ContentMakerForRole forRole(String role) {
    return new ContentMakerForRole(role);
  }
Creates a ContentMakerForRole for a given role.

@param role Currently accepted role values are: "user", "model". No need to call forRole for
    the "user" role since it's the default role.
java-vertexai/google-cloud-vertexai/src/main/java/com/google/cloud/vertexai/generativeai/ContentMaker.java