diff --git a/pkg/resourceprovider/provider.go b/pkg/resourceprovider/provider.go
index 7dda7793..b1dc0151 100644
--- a/pkg/resourceprovider/provider.go
+++ b/pkg/resourceprovider/provider.go
@@ -118,6 +118,7 @@ type nsQueryResults struct {
 	err       error
 }
 
+// GetContainerMetrics implements the provider.MetricsProvider interface. It may return nil, nil, nil.
 func (p *resourceProvider) GetContainerMetrics(pods ...apitypes.NamespacedName) ([]provider.TimeInfo, [][]metrics.ContainerMetrics, error) {
 	if len(pods) == 0 {
 		return nil, nil, nil
@@ -238,6 +239,7 @@ func (p *resourceProvider) assignForPod(pod apitypes.NamespacedName, resultsByNs
 	*resMetrics = containerMetricsList
 }
 
+// GetNodeMetrics implements the provider.MetricsProvider interface. It may return nil, nil, nil.
 func (p *resourceProvider) GetNodeMetrics(nodes ...string) ([]provider.TimeInfo, []corev1.ResourceList, error) {
 	if len(nodes) == 0 {
 		return nil, nil, nil