diff --git a/homeassistant/components/caldav/calendar.py b/homeassistant/components/caldav/calendar.py
index 712873e51ceb..57bf8e81e03e 100644
--- a/homeassistant/components/caldav/calendar.py
+++ b/homeassistant/components/caldav/calendar.py
@@ -87,6 +87,7 @@ def setup_platform(
     calendars = client.principal().calendars()
 
     calendar_devices = []
+    device_id: str | None
     for calendar in list(calendars):
         # If a calendar name was given in the configuration,
         # ignore all the others
diff --git a/requirements_test.txt b/requirements_test.txt
index e043497c4a8e..9a7dd9b23da8 100644
--- a/requirements_test.txt
+++ b/requirements_test.txt
@@ -36,6 +36,7 @@ tqdm==4.65.0
 types-atomicwrites==1.4.5.1
 types-croniter==1.0.6
 types-backports==0.1.3
+types-caldav==1.2.0.2
 types-chardet==0.1.5
 types-decorator==5.1.8.3
 types-enum34==1.1.8