input: def evaluate_model_accuracy(clf, X_train, y_train, X_test, y_test):
      """Evaluates the accuracy of a given machine-learning model.
      >>> clf = SVC(kernel='poly', degree=2, gamma=0.05)
      >>> clf.fit(X_train, y_train)
      >>> y_pred = clf.predict(X_test)
      >>> accuracy = accuracy_score(y_test, y_pred)
      >>> print("Accuracy: " + str(accuracy))
      """
      pass
output:     clf.fit(X_train, y_train)
      y_pred = clf.predict(X_test)
      accuracy = accuracy_score(y_test, y_pred)
      return accuracy