private void ValidateId(Vocabulary vocab, ValidationResult<Vocabulary> result)
{
if (String.IsNullOrWhiteSpace(vocab.Id))
{
result.Errors.Add("The Id must not be blank", v => v.Id);
}
if (vocab.Id.EndsWith("/"))
{
result.Errors.Add("The Id must not end with a slash", v => v.Id);
}
//todo: validate ID format
}