def bubbleSort(alist):
    for passnum in range(len(alist) - 1, 0, -1):
        for i in range(passnum):
            if alist[i] > alist[i + 1]:
                temp = alist[i]
                alist[i] = alist[i + 1]
                alist[i + 1] = temp
    return alist

alist = [54, 26, 93, 17, 77, 31, 44, 55, 20]
print(bubbleSort(alist))