diff --git a/python/core/additions/qgsfeature.py b/python/core/additions/qgsfeature.py
index bf0100ab01dc..6ba45b476370 100644
--- a/python/core/additions/qgsfeature.py
+++ b/python/core/additions/qgsfeature.py
@@ -21,7 +21,7 @@
 
 def mapping_feature(feature):
     geom = feature.geometry()
-    properties = {k: None if (v is None or isinstance(v, QVariant) and v.isNull()) else v for k, v in feature.attributeMap().items()}
+    properties = {k: None if (v is None or (isinstance(v, QVariant) and v.isNull())) else v for k, v in feature.attributeMap().items()}
     return {'type': 'Feature',
             'properties': properties,
             'geometry': geom.__geo_interface__}