diff --git a/src/calibre/devices/idevice/libimobiledevice.py b/src/calibre/devices/idevice/libimobiledevice.py
index de31a2f073..5446366584 100644
--- a/src/calibre/devices/idevice/libimobiledevice.py
+++ b/src/calibre/devices/idevice/libimobiledevice.py
@@ -16,8 +16,9 @@ import os, sys
 
 from collections import OrderedDict
 from ctypes import (
-    c_int, c_long, c_void_p, c_char_p, Structure, POINTER, byref, cdll, c_char, c_ulonglong,
-    c_uint, c_ubyte, create_string_buffer, string_at)
+    byref, cdll, create_string_buffer,
+    c_char, c_char_p, c_int, c_long, c_ubyte, c_uint, c_ulonglong, c_void_p,
+    POINTER, string_at, Structure)
 
 from calibre.constants import DEBUG, islinux, isosx, iswindows
 from calibre.devices.idevice.parse_xml import XmlPropertyListParser