fix: linting

ecommerce/coupons/tests/test_views.py

@@ -438,10 +438,10 @@ def test_invalid_voucher_code(self):
         expected_message = 'No voucher found with code {code}'.format(code=code)
         url = format_url(base=self.redeem_url, params={'code': code, 'sku': self.stock_record.partner_sku})
         response = self.client.get(url, follow=True)
-        
+
         messages = []
         messages += response.context['messages']
-        
+
         self.assertEqual(messages[0].tags, 'error')
         self.assertEqual(messages[0].message, expected_message)
         self.assert_redemption_page_redirects(self.get_coupon_redeem_success_expected_redirect_url())