public static function findRemovedTypes(
        Schema $oldSchema,
        Schema $newSchema
    ) {
        $oldTypeMap = $oldSchema->getTypeMap();
        $newTypeMap = $newSchema->getTypeMap();

        $breakingChanges = [];
        foreach (array_keys($oldTypeMap) as $typeName) {
            if (isset($newTypeMap[$typeName])) {
                continue;
            }

            $breakingChanges[] = [
                'type'        => self::BREAKING_CHANGE_TYPE_REMOVED,
                'description' => "${typeName} was removed.",
            ];
        }

        return $breakingChanges;
    }