Fix docstring

Author: bouwew

plugwise/__init__.py

@@ -603,7 +603,7 @@ async def _set_schedule_state_legacy(
         self._schedule_old_states[loc_id][name] = new_state
 
     def determine_contexts(self, loc_id: str, name: str, state: str, sched_id: str) -> etree:
-        """Helper function for set_schedule_state()."""
+        """Helper-function for set_schedule_state()."""
         locator = f'.//*[@id="{sched_id}"]/contexts'
         contexts = self._domain_objects.find(locator)
         locator = f'.//*[@id="{loc_id}"].../...'