input: 
  def construct_naive_bayes_classifier() -> GaussianNB:
      """Construct a naive bayes classifier using python to classify emails as spam or not spam.
      >>> from sklearn.naive_bayes import GaussianNB
      >>> model = construct_naive_bayes_classifier()
      >>> model.fit(X_train, y_train)
      >>> y_pred = model.predict(X_test)
      """
      from sklearn.naive_bayes import GaussianNB
      return GaussianNB()
  
output:     from sklearn.naive_bayes import GaussianNB
      return GaussianNB()