diff --git a/config.go b/config.go
index bf523655..7f1bcc96 100644
--- a/config.go
+++ b/config.go
@@ -57,6 +57,10 @@ func (n Namespaces) index(t NamespaceType) int {
 	return -1
 }
 
+func (n Namespaces) Contains(t NamespaceType) bool {
+	return n.index(t) != -1
+}
+
 // Config defines configuration options for executing a process inside a contained environment.
 type Config struct {
 	// Mount specific options.
diff --git a/config_test.go b/config_test.go
index 63b8aa8a..5c73f84a 100644
--- a/config_test.go
+++ b/config_test.go
@@ -64,12 +64,12 @@ func TestConfigJsonFormat(t *testing.T) {
 		t.Fail()
 	}
 
-	if container.Namespaces.index(NEWNET) == -1 {
+	if !container.Namespaces.Contains(NEWNET) {
 		t.Log("namespaces should contain NEWNET")
 		t.Fail()
 	}
 
-	if container.Namespaces.index(NEWUSER) != -1 {
+	if container.Namespaces.Contains(NEWUSER) {
 		t.Log("namespaces should not contain NEWUSER")
 		t.Fail()
 	}