import static org.opendaylight.yangtools.yang.data.impl.schema.ImmutableNodes.mapEntryBuilder;
import static org.opendaylight.yangtools.yang.data.impl.schema.ImmutableNodes.mapNodeBuilder;
-import com.google.common.base.Optional;
+import java.util.Optional;
import org.junit.Before;
import org.junit.Test;
import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;