diff --git a/src/watchdog/observers/polling.py b/src/watchdog/observers/polling.py
index 466cd821..af74a6c5 100644
--- a/src/watchdog/observers/polling.py
+++ b/src/watchdog/observers/polling.py
@@ -49,7 +49,7 @@
     FileMovedEvent,
 )
 from watchdog.observers.api import DEFAULT_EMITTER_TIMEOUT, DEFAULT_OBSERVER_TIMEOUT, BaseObserver, EventEmitter
-from watchdog.utils.dirsnapshot import DirectorySnapshot, DirectorySnapshotDiff
+from watchdog.utils.dirsnapshot import DirectorySnapshot, DirectorySnapshotDiff, EmptyDirectorySnapshot
 
 
 class PollingEmitter(EventEmitter):
@@ -68,7 +68,7 @@ def __init__(
         listdir=os.scandir,
     ):
         super().__init__(event_queue, watch, timeout, event_filter)
-        self._snapshot = None
+        self._snapshot: DirectorySnapshot = EmptyDirectorySnapshot()
         self._lock = threading.Lock()
         self._take_snapshot = lambda: DirectorySnapshot(
             self.watch.path, self.watch.is_recursive, stat=stat, listdir=listdir
diff --git a/src/watchdog/utils/dirsnapshot.py b/src/watchdog/utils/dirsnapshot.py
index 282487ba..69f41608 100644
--- a/src/watchdog/utils/dirsnapshot.py
+++ b/src/watchdog/utils/dirsnapshot.py
@@ -356,12 +356,15 @@ def __repr__(self) -> str:
         return str(self._stat_info)
 
 
-class EmptyDirectorySnapshot:
+class EmptyDirectorySnapshot(DirectorySnapshot):
     """Class to implement an empty snapshot. This is used together with
     DirectorySnapshot and DirectorySnapshotDiff in order to get all the files/folders
     in the directory as created.
     """
 
+    def __init__(self):
+        pass
+
     @staticmethod
     def path(_: Any) -> None:
         """Mock up method to return the path of the received inode. As the snapshot