fix build feature bug

ml/dt_factory.py

@@ -242,6 +242,8 @@ def build_feature(feature):
         APP_LOGGER.debug("Adding feature: %s" % feature_class_name)
         feature_instance = feature_obj()
         for key in feature.keys():
+            if key == "class":
+                continue
             if key == "targets":
                 build_sub_thing(feature_instance, feature)
             elif key == "subFeatures":