I want to Support Update in TranslationMemory provider plugin,

in the class TranslateProvider : ITranslationProvider there is 

public bool SupportsUpdate
{
get
{
return false;
}
}

I changed it to true and I think I should implement some methods in TranslationProviderLanguageDirection class like 

public ImportResult[] AddOrUpdateTranslationUnits(TranslationUnit[] translationUnits, int[] previousTranslationHashes, ImportSettings settings)
{
throw new NotImplementedException();
}

public ImportResult[] AddOrUpdateTranslationUnitsMasked(TranslationUnit[] translationUnits, int[] previousTranslationHashes, ImportSettings settings, bool[] mask)
{
throw new NotImplementedException();
}

public ImportResult AddTranslationUnit(TranslationUnit translationUnit, ImportSettings settings)
{
throw new NotImplementedException();
}

public ImportResult[] AddTranslationUnits(TranslationUnit[] translationUnits, ImportSettings settings)
{
throw new NotImplementedException();
}

public ImportResult[] AddTranslationUnitsMasked(TranslationUnit[] translationUnits, ImportSettings settings, bool[] mask)
{
throw new NotImplementedException();
}

public ImportResult UpdateTranslationUnit(TranslationUnit translationUnit)
{
throw new NotImplementedException();
}

public ImportResult[] UpdateTranslationUnits(TranslationUnit[] translationUnits)
{
throw new NotImplementedException();
}

but I do not know how ?