public function generateRemovedFields()
    {
        foreach ($this->keptModelKeys as $modelName) {
            $oldFieldKeys = $this->oldFieldKeys[$modelName];
            $newFieldKeys = $this->newFieldKeys[$modelName];

            $remFields = array_diff($oldFieldKeys, $newFieldKeys);

            foreach ($remFields as $remField) {
                $this->findRemovedFields($modelName, $remField);
            }
        }
    }