def calculate_accuracy(combined_decisions, Y_test_1):
    """calculates percentage accuracy of a combined decisions array

    Args:
        combined_decisions: predicted values for combined model
        Y_test_1: True values
    Returns:
       percentage accuracy of predictions
    """
    total_decisions = len(combined_decisions)
    correct_decisions = 0
    for index, decision in combined_decisions:
        if decision == Y_test_1[index]:
            correct_decisions +=1
    return correct_decisions / total_decisions * 100