fix flux_update service

homeassistant/components/switch/flux.py

@@ -151,8 +151,9 @@ class FluxSwitch(SwitchDevice):
         self.update_ha_state()
 
     # pylint: disable=too-many-locals
-    def flux_update(self, now=dt_now()):
+    def flux_update(self, service=None):
         """Update all the lights using flux."""
+        now = dt_now()
         sunset = next_setting(self.hass, SUN).replace(day=now.day,
                                                       month=now.month,
                                                       year=now.year)