yii\db\ActiveQueryTrait::normalizeRelations PHP Method

    private function normalizeRelations($model, $with)
    {
        $relations = [];
        foreach ($with as $name => $callback) {
            if (is_int($name)) {
                $name = $callback;
                $callback = null;
            }
            if (($pos = strpos($name, '.')) !== false) {
                // with sub-relations
                $childName = substr($name, $pos + 1);
                $name = substr($name, 0, $pos);
            } else {
                $childName = null;
            }
            if (!isset($relations[$name])) {
                $relation = $model->getRelation($name);
                $relation->primaryModel = null;
                $relations[$name] = $relation;
            } else {
                $relation = $relations[$name];
            }
            if (isset($childName)) {
                $relation->with[$childName] = $callback;
            } elseif ($callback !== null) {
                call_user_func($callback, $relation);
            }
        }
        return $relations;
    }