*/
package org.opendaylight.yangtools.yang.parser.stmt.reactor;
-import com.google.common.base.Optional;
import com.google.common.base.Preconditions;
import com.google.common.base.Verify;
import com.google.common.collect.ImmutableList;
import java.util.Collection;
import java.util.HashSet;
import java.util.Map;
+import java.util.Optional;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import org.opendaylight.yangtools.yang.common.QNameModule;