input: def naive_bayes_classifier(X_train, y_train, X_test):
      """ Construct a naive bayes classifier using python to classify emails as spam or not spam.
      >>> naive_bayes_classifier([[1, 2], [3, 4]], [0, 1], [[1, 1]])
      [0]
      >>> naive_bayes_classifier([[1, 2], [3, 4]], [1, 0], [[2, 2]])
      [1]
      """
      from sklearn.naive_bayes import GaussianNB
      
      # Create a Gaussian Classifier
      model = GaussianNB()
      
      # Train the model using the training sets 
      model.fit(X_train, y_train)
      
      # Predict Output 
      y_pred = model.predict(X_test)
      
      return y_pred
output:     from sklearn.naive_bayes import GaussianNB
      
      # Create a Gaussian Classifier
      model = GaussianNB()
      
      # Train the model using the training sets 
      model.fit(X_train, y_train)
      
      # Predict Output 
      y_pred = model.predict(X_test)
      
      return y_pred