diff --git a/roaring/containers.go b/roaring/containers.go
index 19871050b..a993ebfdb 100644
--- a/roaring/containers.go
+++ b/roaring/containers.go
@@ -21,7 +21,7 @@ type SliceContainers struct {
 	lastContainer *Container
 }
 
-func NewSliceContainers() *SliceContainers {
+func newSliceContainers() *SliceContainers {
 	return &SliceContainers{}
 }
 
@@ -102,7 +102,7 @@ func (sc *SliceContainers) GetOrCreate(key uint64) *Container {
 }
 
 func (sc *SliceContainers) Clone() Containers {
-	other := NewSliceContainers()
+	other := newSliceContainers()
 	other.keys = make([]uint64, len(sc.keys))
 	other.containers = make([]*Container, len(sc.containers))
 	copy(other.keys, sc.keys)
diff --git a/roaring/roaring.go b/roaring/roaring.go
index ab4c1cabd..c15b965e1 100644
--- a/roaring/roaring.go
+++ b/roaring/roaring.go
@@ -117,7 +117,7 @@ type Bitmap struct {
 // NewBitmap returns a Bitmap with an initial set of values.
 func NewBitmap(a ...uint64) *Bitmap {
 	b := &Bitmap{
-		Containers: NewSliceContainers(),
+		Containers: newSliceContainers(),
 	}
 	b.Add(a...)
 	return b