Customizing Spacy's Text Categorizer

I am trying to to train a spacy model with a small dataset in Spacy 2.2. It is overfitting, I want to customize the architecture of the TextCategorizer. I referred to this post on GitHub :

https://github.com/explosion/spaCy/issues/3320

However, I am unable

from spacy.pipeline import TextCategorizer
from thinc.api import layerize
from spacy.language import Language

class StupidTextCategorizer(TextCategorizer):
    name = 'stupid_textcat'
    @classmethod

    def Model(cls, nr_class, **cfg):
        return create_dummy_model(nr_class, cfg.get('preferred_class', 0))

def create_dummy_model(nr_class, preferred_class):
    """Create a Thinc model that always predicts the same class."""
    def dummy_model(docs, drop=0.):
        scores = model.ops.allocate((len(docs), nr_class))
        scores[:, preferred_class] = 1.0
        return scores
        
    model = layerize(dummy_model)
    return model

However, when I'm trying to pass it to my training script, it throws this error which I can't seem to understand.

"[E002] Can't find factory for 'stupid_textcat'. This usually happens when spaCy calls `nlp.create_pipe` with a component name that's not built in - for example, when constructing the pipeline from a model's meta.json. If you're using a custom component, you can write to `Language.factories['stupid_textcat']` or remove it from the model meta and add it via `nlp.add_pipe` instead."

PS : Still learning Spacy but I can't find any helping documentation or tutorial for the above.