-import org.opendaylight.controller.yang.model.api.TypeDefinition;
-import org.opendaylight.controller.yang.model.api.type.UnionTypeDefinition;
-import org.opendaylight.controller.yang.model.util.ExtendedType;
-import org.opendaylight.controller.yang.parser.util.TopologicalSort;
-import org.opendaylight.controller.yang.parser.util.TopologicalSort.Node;
-import org.opendaylight.controller.yang.parser.util.TopologicalSort.NodeImpl;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-import java.util.List;
-import java.util.Map;
-import java.util.Set;