leetcode 1796. Second Largest Digit in a String

class Solution:
    def secondHighest(self, s: str) -> int:
        num_list=[]
        for i in s:
            if i.isdecimal() : num_list.append(int(i))
        num_list=sorted(list(set(num_list)), reverse=True)
        if len(num_list)<2: ans=-1
        else :ans = (num_list[1])
        return(ans)