input: 
  def naive_bayes_classifier(X_train, y_train, X_test):
      """Constructs a simple naive bayes classifier using the GaussianNB model from sklearn
      to classify emails as spam or not spam. It trains the model on the provided training 
      data and predicts the classification for the test data.
      >>> naive_bayes_classifier([[1, 2], [2, 3], [3, 4]], [0, 1, 1], [[1, 1], [3, 3]])
      [0, 1]
      """
  
output:     from sklearn.naive_bayes import GaussianNB
      model = GaussianNB()
      model.fit(X_train, y_train)
      return model.predict(X_test)