public ArchiveNode getNodeForManager(DataTypeManager dtm) {
		for (GTreeNode node : getChildren()) {
			ArchiveNode archiveNode = (ArchiveNode) node;
			Archive archive = archiveNode.getArchive();
			DataTypeManager manager = archive.getDataTypeManager();
			if (manager.equals(dtm)) {
				return archiveNode;
			}
		}
		return null;
	}
This implementation returns null, since this class is the root of the hierarchy and does
not have an archive.
@see ghidra.app.plugin.core.datamgr.tree.DataTypeTreeNode#getArchiveNode()
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/datamgr/tree/ArchiveRootNode.java