diff --git a/src/calibre/utils/config.py b/src/calibre/utils/config.py
index 2ca0139bba..a764b907b8 100644
--- a/src/calibre/utils/config.py
+++ b/src/calibre/utils/config.py
@@ -19,7 +19,7 @@ from calibre.constants import (
 from calibre.utils.config_base import (
     Config, ConfigInterface, ConfigProxy, Option, OptionSet, OptionValues,
     StringConfig, json_dumps, json_loads, make_config_dir, plugin_dir, prefs,
-    read_raw_tweaks, read_tweaks, tweaks, write_tweaks
+    read_raw_tweaks, read_tweaks, tweaks, write_tweaks, from_json, to_json
 )
 from calibre.utils.lock import ExclusiveFile
 
@@ -32,7 +32,7 @@ if False:
     # Make pyflakes happy
     Config, ConfigProxy, Option, OptionValues, StringConfig
     OptionSet, ConfigInterface, read_tweaks, write_tweaks
-    read_raw_tweaks, tweaks, plugin_dir, prefs
+    read_raw_tweaks, tweaks, plugin_dir, prefs, from_json, to_json
 
 
 def check_config_write_access():