leetcode (21) - full array

class Solution:
    def permute(self, nums):
        res = []
        def func(ans,num):
            if len(num)==0:
                res.append(ans)
            for i in range(len(num)):
                each = num[i]
                t = ans.copy()
                t.append(each)
                func(t,num[:i]+num[i+1:]) 
        func([],nums)
        return res
s = Solution()
print(s.permute([1,2,3]))