[databases][serializers] Fix key search in dictionary

beat/web/databases/serializers.py

@@ -101,7 +101,7 @@ class DatabaseCreationSerializer(serializers.ModelSerializer):
         name = self.Meta.model.sanitize_name(data['name'])
         data['name'] = name
 
-        if data.has_key('previous_version'):
+        if 'previous_version' in data:
             previous_version_id = self.Meta.beat_core_class.Storage(settings.PREFIX,
                                                                     data['previous_version'])
         else: