diff --git a/pytautulli/models/activity.py b/pytautulli/models/activity.py
index <HASH>..<HASH> 100644
--- a/pytautulli/models/activity.py
+++ b/pytautulli/models/activity.py
@@ -19,4 +19,6 @@ class PyTautulliApiActivity(PyTautulliApiBaseModel):
 
     def __post_init__(self):
         super().__post_init__()
-        self.sessions = [PyTautulliApiSession(session) for session in self.sessions]
+        self.sessions = [
+            PyTautulliApiSession(session) for session in self.sessions or []
+        ]
Fixes issue with iterating sessions when they are None (#<I>)