public void removeTestingCallback(OneSheeldTestingCallback testingCallback){
  if (testingCallback != null && testingCallbacks.contains(testingCallback))   testingCallbacks.remove(testingCallback);
}

public void removeTestingCallback ( OneSheeldTestingCallback testingCallback ) { if ( testingCallback != null && testingCallbacks . contains ( testingCallback ) ) testingCallbacks . remove ( testingCallback ) ; }
remove a testing callback .
