def test(l):
ans = 0
def getListNumber(l):
nonlocal ans
for item in l:
if isinstance(item, list):
ans += 1
getListNumber(item)
return ans
return getListNumber(l)

if __name__ == '__main__':
List = [[1, 2, [3, [2], [1, 2]]]]
print(test(List))