-import java.util.SortedSet;
-import java.util.TreeSet;
-import org.opendaylight.yangtools.yang.model.api.DataSchemaNode;
-import org.opendaylight.yangtools.yang.model.api.AnyXmlSchemaNode;
-import org.opendaylight.yangtools.yang.model.api.LeafSchemaNode;
-import org.opendaylight.yangtools.yang.model.api.LeafListSchemaNode;
-import org.opendaylight.yangtools.yang.model.api.ListSchemaNode;
-import org.opendaylight.yangtools.yang.model.api.ContainerSchemaNode;
-import org.opendaylight.yangtools.yang.parser.builder.util.Comparators;
-import org.opendaylight.yangtools.yang.parser.spi.meta.StmtContext.TypeOfCopy;
-import java.util.Collection;
-import java.util.HashSet;
-import java.util.LinkedList;
-import org.opendaylight.yangtools.yang.parser.stmt.rfc6020.Utils;
-import org.opendaylight.yangtools.yang.model.api.meta.EffectiveStatement;
-import org.opendaylight.yangtools.yang.model.api.stmt.ChoiceStatement;
-import org.opendaylight.yangtools.yang.parser.spi.meta.StmtContext;