diff --git a/aurora/models/change.py b/aurora/models/change.py
index c02fb00..e9f376f 100644
--- a/aurora/models/change.py
+++ b/aurora/models/change.py
@@ -40,16 +40,16 @@ class Change(AuroraBaseModel):
             data = json.loads(data)
         if data.get('duration'):
             logger.debug(f"Duration: {data['duration']}")
-        if "duration" in data and data["duration"] and not isinstance(data["duration"], timedelta) and not data["duration"] == "NULL":
+        if data.get('duration') and not isinstance(data["duration"], timedelta) and not data["duration"] == "NULL":
             duration = timedelta_from_string(data["duration"])
-        elif "duration" in data and isinstance(data["duration"], timedelta):
+        elif data.get('duration') and isinstance(data["duration"], timedelta):
             duration = data["duration"]
         else:
             duration = None
 
-        if "end_timestamp" in data and data["end_timestamp"] and not isinstance(data["end_timestamp"], datetime):
+        if data.get('end_timestamp') and not isinstance(data["end_timestamp"], datetime):
             end_timestamp = datetime.fromtimestamp(data["end_timestamp"])
-        elif "end_timestamp" in data and isinstance(data["end_timestamp"], datetime):
+        elif data.get('end_timestamp') and isinstance(data["end_timestamp"], datetime):
             end_timestamp = data["end_timestamp"]
         else:
             end_timestamp = None