code: @SuppressWarnings("unused")
      public String getDevicePushToken(final PushType type) {
          switch (type) {
              case GCM:
                  return getCachedGCMToken();
              case FCM:
                  return getCachedFCMToken();
              default:
                  return null;
          }
      }
docs: Returns the device push token or null
  
  @param type com.clevertap.android.sdk.PushType (FCM or GCM)
  @return String device token or null
  NOTE: on initial install calling getDevicePushToken may return null, as the device token is
  not yet available
  Implement CleverTapAPI.DevicePushTokenRefreshListener to get a callback once the token is
  available