Maximum xor of any two elements in given array

class Solution:
    def findMaximumXOR(self, nums: List[int]) -> int:
        root={}
        def add(word):
            cur=root
            for i in range(31,-1,-1):
                t=1 if (1<<i) & word else 0
                if t in cur:
                    cur=cur[t]
                else:
                    cur[t]={}
                    cur=cur[t]

        for word in nums:
            add(word)
        ans=0
        for num in nums:
            cur=root
            curans=0
            for i in range(31,-1,-1):
                dig=1 if num & (1<<i) else 0
                if 1-dig in cur:
                    cur=cur[1-dig]
                    curans=curans |(1<<i)
                else:
                    cur=cur[dig]
            ans=max(ans,curans)
        return ans