code: List<String> validate(Asset asset) throws APIException, ConnectionException, OidException {
          List<IAttributeDefinition> result = validator.validate(asset);
          return getAttributeNames(result);
      }
docs: Pass asset to required field validator.
  We cannot resolve asset by AssetID because in newly created entities it is null until Commit() is actually executed, that's why it is used directly.
  @param asset - Asset to validate.
  @return Collection of invalid attribute names.
  @throws OidException
  @throws ConnectionException
  @throws APIException