Follow isort formatting

issue10928

trytond/model/fields/function.py

@@ -1,8 +1,8 @@
 # This file is part of Tryton.  The COPYRIGHT file at the top level of
 # this repository contains the full copyright notices and license terms.
 
-import inspect
 import copy
+import inspect
 from functools import wraps
 
 from trytond.i18n import gettext