请问我的这段代码有什么问题吗(冒泡排序的代码)

def transform(arr):
    """将字符串变成字符串列表"""
    new_arr = arr.strip("[")
    new_arr = new_arr.strip("]")
    new_arr = new_arr.split(",")
    return new_arr

def change_type(arr):
    """将字符串列表变成数字列表"""
    for num in arr:
        num = int(num)
        new_arr.append(num)
    return new_arr


def exchange(arr):
    """交换数字"""
    for i in range(len(arr)):
        for j in range(len(arr)-1):
            if arr[j] > arr[j+1]:
                arr[j], arr[j+1] = arr[j+1], arr[j]
    return arr


arr = input()
new_arr = transform(arr)
new_arr = change_type(new_arr)
arr = exchange(new_arr)
print(arr)

改成这样
def change_type(arr):
    """将字符串列表变成数字列表"""
    x = []
    for num in arr:
        num = int(num)
        x.append(num)
    return x