input: def classify_emails(X_train, y_train, X_test):
      """ Implements a naive bayes classifier using python to classify emails as spam or not spam.
      >>> classify_emails([[1, 2], [2, 3], [3, 4]], [0, 1, 1], [[1, 1], [2, 2]])
      [0, 1]
      """
      from sklearn.naive_bayes import GaussianNB
      model = GaussianNB()
      model.fit(X_train, y_train)
      return model.predict(X_test)
output:     from sklearn.naive_bayes import GaussianNB
      model = GaussianNB()
      model.fit(X_train, y_train)
      return model.predict(X_test)