Minor fix

shift.py

@@ -1,6 +1,7 @@
 # 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 datetime
+from datetime import datetime, timedelta, time
+
 from trytond.model import Workflow, ModelView, ModelSQL, fields
 from trytond.wizard import Wizard, StateView, Button, StateTransition
 from trytond.pyson import Eval
@@ -159,11 +160,11 @@ class AddShift(Wizard):
         if ids:
             shift = Shift(ids[0])
             lines_to_create = []
-            enter_hour_tz = datetime.time(
+            enter_hour_tz = time(
                     self.start.enter_hour.hour + 5,
                     self.start.enter_hour.minute)
-            enter_ = datetime.datetime.combine(shift.shift_date, enter_hour_tz)
-            exit_ = enter_ + datetime.timedelta(0, self.start.timework * 3600)
+            enter_ = datetime.combine(shift.shift_date, enter_hour_tz)
+            exit_ = enter_ + timedelta(0, self.start.timework * 3600)
             for e in self.start.employees:
                 lines_to_create.append({
                     'employee': e.id,