Adding more features to featurizers

Is it possible to feed the state featurizers with other features than those mentioned here ? For instance, suppose that I want to add (I am going to say to some rubish) the number of verbs in a sentence etc… and I want my policies models to use these as additional features . How can we deal with this?

you need to create custom featurizer and feed it to the policy

Do you have any tutorial for create a custom featurizer ?

we have docs on how to create custom components: Custom NLU Components