diff --git a/core/includes/update.inc b/core/includes/update.inc
index c16d0ef1c3..7bc0e6010a 100644
--- a/core/includes/update.inc
+++ b/core/includes/update.inc
@@ -374,7 +374,7 @@ function update_resolve_dependencies($starting_updates) {
   $graph_object = new Graph($graph);
   $graph = $graph_object->searchAndSort();
   // Prepare the graph for sort.
-  update_prepare_graph_for_sort($graph);
+  _update_prepare_graph_for_sort($graph);
   // Finally sort the updates by weight.
   uasort($graph, ['Drupal\Component\Utility\SortArray', 'sortByWeightElement']);
 
@@ -443,8 +443,10 @@ function update_resolve_dependencies($starting_updates) {
  *
  * @param array &$graph
  *   The update graph array.
+ *
+ * @internal
  */
-function update_prepare_graph_for_sort(array &$graph) {
+function _update_prepare_graph_for_sort(array &$graph) {
   $weights = [];
   $system_updates = [];
   foreach ($graph as $update_name => $update_data) {
@@ -455,7 +457,7 @@ function update_prepare_graph_for_sort(array &$graph) {
     }
   }
   sort($weights);
-  $new_weights  = array_combine($weights, $weights);
+  $new_weights = array_combine($weights, $weights);
   foreach ($system_updates as $system_update_weight) {
     foreach ($new_weights as $old_weight => &$new_weight) {
       if ($old_weight >= $system_update_weight) {
@@ -591,7 +593,7 @@ function update_build_dependency_graph($update_functions) {
 
   // A function returning all the updates which directly or indirectly have a
   // specific update as an edge.
-  $get_all_parents = function($update) use ($graph, &$get_all_parents) {
+  $get_all_parents = function ($update) use ($graph, &$get_all_parents) {
     $parents = [];
     foreach ($graph as $func => $data) {
       if (isset($data['edges'][$update])) {