def METHOD_NAME(training_data):
    X_train, y_train = training_data
    # Initiate and fit the tokenizer on the training data and transform the training dataset
    vectorizer = TfidfVectorizer()
    transformed_X_train = vectorizer.fit_transform(X_train)
    transformed_X_train = transformed_X_train.toarray()
    y_train = y_train.fillna(0)
    transformed_y_train = np.array(y_train)
    return vectorizer, (transformed_X_train, transformed_y_train)