input: Write a function to develop a machine learning algorithm in Python to identify apples from bananas. The function should load data, initialize a classifier, fit the data, and test the classifier. The function should return the predictions for the test data.
  assert identify_fruit(np.array([[1,2,3], [-1,2,5], [-1,2,7], [5,5,5], [3,3,3], [5,5,7]]), np.array([0, 0, 0, 1, 0, 1]), np.array([[2,2,2], [4,4,4]]))==[0, 1]
output: def identify_fruit(X_train, y_train, X_test):
      from sklearn.tree import DecisionTreeClassifier
      classifier = DecisionTreeClassifier()
      classifier.fit(X_train, y_train)
      predictions = classifier.predict(X_test)
      return predictions