diff --git a/homeassistant/components/nuki/lock.py b/homeassistant/components/nuki/lock.py
index 765fc5f711f..33d7465e12d 100644
--- a/homeassistant/components/nuki/lock.py
+++ b/homeassistant/components/nuki/lock.py
@@ -2,6 +2,7 @@
 from abc import ABC, abstractmethod
 from typing import Any
 
+from pynuki import NukiLock, NukiOpener
 from pynuki.constants import MODE_OPENER_CONTINUOUS
 import voluptuous as vol
 
@@ -73,11 +74,6 @@ class NukiDeviceEntity(NukiEntity, LockEntity, ABC):
         """Return a unique ID."""
         return self._nuki_device.nuki_id
 
-    @property
-    @abstractmethod
-    def is_locked(self):
-        """Return true if lock is locked."""
-
     @property
     def extra_state_attributes(self):
         """Return the device specific state attributes."""
@@ -108,8 +104,10 @@ class NukiDeviceEntity(NukiEntity, LockEntity, ABC):
 class NukiLockEntity(NukiDeviceEntity):
     """Representation of a Nuki lock."""
 
+    _nuki_device: NukiLock
+
     @property
-    def is_locked(self):
+    def is_locked(self) -> bool:
         """Return true if lock is locked."""
         return self._nuki_device.is_locked
 
@@ -137,8 +135,10 @@ class NukiLockEntity(NukiDeviceEntity):
 class NukiOpenerEntity(NukiDeviceEntity):
     """Representation of a Nuki opener."""
 
+    _nuki_device: NukiOpener
+
     @property
-    def is_locked(self):
+    def is_locked(self) -> bool:
         """Return true if either ring-to-open or continuous mode is enabled."""
         return not (
             self._nuki_device.is_rto_activated