diff --git a/src/calibre/gui2/icon_theme.py b/src/calibre/gui2/icon_theme.py
index 59d97928c3..7c0ba8271d 100644
--- a/src/calibre/gui2/icon_theme.py
+++ b/src/calibre/gui2/icon_theme.py
@@ -38,7 +38,7 @@ from calibre.utils.img import image_from_data, Canvas, optimize_png, optimize_jp
 from calibre.utils.zipfile import ZipFile, ZIP_STORED
 from calibre.utils.filenames import atomic_rename
 from lzma.xz import compress, decompress
-from polyglot.builtins import iteritems, map, range, reraise, filter, as_bytes
+from polyglot.builtins import iteritems, map, range, reraise, filter, as_bytes, unicode_type
 from polyglot import http_client
 from polyglot.queue import Queue, Empty