def bubble_sort(arr) -> int:

    n = len(arr)

    for i in range(n):
        for x in range(n-i-1):
            if arr[x] > arr[x+1]:
                arr[x], arr[x + 1] = arr[x + 1], arr[x]

    return arr


print(bubble_sort([64, 34, 25, 12, 22, 11, 90]))