Reset Brottsplatskartan incident types every day (#20117)

* Reset the incident types count every day

* Remove functionality that was never implemented

We don't need to keep track of previous incidents because it's not used
anywhere.

* Create empty dictionary with a pair of braces: {}

homeassistant/components/sensor/brottsplatskartan.py

@@ -69,11 +69,9 @@ class BrottsplatskartanSensor(Entity):
 
     def __init__(self, bpk, name):
         """Initialize the Brottsplatskartan sensor."""
-        import brottsplatskartan
-        self._attributes = {ATTR_ATTRIBUTION: brottsplatskartan.ATTRIBUTION}
+        self._attributes = {}
         self._brottsplatskartan = bpk
         self._name = name
-        self._previous_incidents = set()
         self._state = None
 
     @property
@@ -93,6 +91,7 @@ class BrottsplatskartanSensor(Entity):
 
     def update(self):
         """Update device state."""
+        import brottsplatskartan
         incident_counts = defaultdict(int)
         incidents = self._brottsplatskartan.get_incidents()
 
@@ -100,13 +99,10 @@ class BrottsplatskartanSensor(Entity):
             _LOGGER.debug("Problems fetching incidents")
             return
 
-        if len(incidents) < len(self._previous_incidents):
-            self._previous_incidents = set()
-
         for incident in incidents:
             incident_type = incident.get('title_type')
             incident_counts[incident_type] += 1
-            self._previous_incidents.add(incident.get('id'))
 
+        self._attributes = {ATTR_ATTRIBUTION: brottsplatskartan.ATTRIBUTION}
         self._attributes.update(incident_counts)
         self._state = len(incidents)