def accuracy(Y_pred, Y_test):
    """
    Calculates the accuracy of the model 
    
    Arguments:
        Y_pred (np.array): shape [n_test_examples,] an array of model predictions
        Y_test (np.array): shape [n_test_labels,] an array of test labels to 
            evaluate the predictions against
    
    Returns:
        accuracy (float): the accuracy of the model
    """
    assert(Y_pred.shape == Y_test.shape)
    
    correct = 0
    total = len(Y_test)

    for i in range(total):
        if (Y_pred[i] == Y_test[i]):
            correct += 1
    
    accuracy = correct/total
    return accuracy