import numpy as np

from typing import Any, Text
from rasa.nlu.training_data import Message
from rasa.nlu.components import Component
from rasa.nlu.constants import MESSAGE_VECTOR_FEATURE_NAMES, MESSAGE_TEXT_ATTRIBUTE


class Featurizer(Component):
    @staticmethod
    def _combine_with_existing_features(
        message: Message,
        additional_features: Any,
        feature_name: Text = MESSAGE_VECTOR_FEATURE_NAMES[MESSAGE_TEXT_ATTRIBUTE],
    ) -> Any:
        if message.get(feature_name) is not None:
            return np.hstack((message.get(feature_name), additional_features))
        else:
            return additional_features

@@ -534,15 +534,37 @@
  np.
-hstack(
+concatenate(%0A                
 (mes
@@ -607,16 +607,38 @@
 eatures)
+, axis=-1%0A            
 )%0A      

concatenate instead of hstack