Clear Digits Python Solution with Tests

lcpy gen -n 3174   # by problem number
lcpy gen -s clear_digits   # by problem name

Input: s = "abc"
Output: "abc"
Explanation: There is no digit in the string.

Input: s = "cb34"
Output: ""
Explanation: First, we apply the operation on s[2], and s becomes "c4".
Then we apply the operation on s[1], and s becomes "".

class Solution:
    # Time: O(n)
    # Space: O(n)
    def clear_digits(self, s: str) -> str:
        stack: list[str] = []
        for char in s:
            if char.isdigit():
                stack.pop()
            else:
                stack.append(char)
        return "".join(stack)