import static org.opendaylight.yangtools.yang.data.api.schema.stream.NormalizedNodeStreamWriter.UNKNOWN_SIZE;
-import com.google.common.base.Optional;
import com.google.common.base.Preconditions;
import com.google.common.collect.Iterables;
import java.io.IOException;
import java.util.Collection;
import java.util.Map;
+import java.util.Optional;
import java.util.Set;
import org.opendaylight.netconf.sal.rest.api.RestconfNormalizedNodeWriter;
import org.opendaylight.yangtools.yang.common.QName;