diff --git a/export.go b/export.go
index f2e49e465..6a6eb5c1c 100644
--- a/export.go
+++ b/export.go
@@ -78,7 +78,7 @@ func newExporterWithOptions(tree *ImmutableTree, optimistic bool) (*Exporter, er
 
 // export exports nodes
 func (e *Exporter) export(ctx context.Context) {
-	e.tree.root.traversePost(e.tree, true, func(node *Node) bool {
+	_ = e.tree.root.traversePost(e.tree, true, func(node *Node) bool {
 		exportNode := &ExportNode{
 			Key:     node.key,
 			Value:   node.value,
diff --git a/import.go b/import.go
index 2499a5627..c76616b00 100644
--- a/import.go
+++ b/import.go
@@ -178,7 +178,9 @@ func (i *Importer) OptimisticAdd(exportNode *ExportNode) error {
 	}
 	i.batchSize++
 
-	i.sendBatchIfFull()
+	if err := i.sendBatchIfFull(); err != nil {
+		return errors.New("failed sending db write batch")
+	}
 
 	return nil
 }
@@ -263,9 +265,8 @@ func (i *Importer) Commit() error {
 		return ErrNoImport
 	}
 
-	if i.optimistic {
-		// All keys should be already imported
-	} else {
+	// Optimistic: All keys should be already imported
+	if !i.optimistic {
 		switch len(i.stack) {
 		case 0:
 			if err := i.batch.Set(i.tree.ndb.nodeKey(GetRootKey(i.version)), []byte{}); err != nil {
diff --git a/node.go b/node.go
index 97d54a865..f035d6645 100644
--- a/node.go
+++ b/node.go
@@ -707,6 +707,7 @@ func (node *Node) calcBalance(t *ImmutableTree) (int, error) {
 }
 
 // traverse is a wrapper over traverseInRange when we want the whole tree
+// nolint: unparam
 func (node *Node) traverse(t *ImmutableTree, ascending bool, cb func(*Node) bool) bool {
 	return node.traverseInRange(t, nil, nil, ascending, false, false, func(node *Node) bool {
 		return cb(node)