docs: public String getVersion(String configString) {
      if (configString == null
          || configString.trim().isEmpty()
          || configString.equals(APPENGINE_CONFIG)) {
        throw new GradleException(VERSION_ERROR);
      }
      if (configString.equals(GCLOUD_CONFIG)) {
        // can be null to allow gcloud to generate this
        return null;
      }
      return configString;
    }