这里的工作代码:

from copy import deepcopy

def how_much_dif_l(arg):
    arg_list=deepcopy(arg)
    i=0
    length=len(arg_list)
    while i<length:
        a = arg_list[i]
        if arg_list.count(a)>1:
            length-=1
            arg_list.remove(a)
        else: 
            i+=1


    return len(arg_list)

list1= [[1,2,3],[1,2,3],[1,2,2],[1,2,2]]
print(how_much_dif_l(list1))