input: Write a function to develop a machine learning algorithm in Python to identify apples from bananas. The function should initialize a classifier, fit the classifier to the provided training data, and then predict the classification for given test data. If the class labels '0' and '1' are used for apples and bananas respectively, the function should return the predicted labels for the test data.
  assert classify_fruit_types() == [0, 1]
output: def classify_fruit_types():
      from sklearn.tree import DecisionTreeClassifier
      train_data = [[1, 1], [2, 2]]
      train_labels = [0, 1]
      test_data = [[1.5, 1.5], [2.5, 2.5]]
      classifier = DecisionTreeClassifier()
      classifier.fit(train_data, train_labels)
      predicted_labels = classifier.predict(test_data)
      return predicted_labels.tolist()