-3.1

def do_rle(s: str) -> list[tuple]:
    ans = []
    c = 1
    for i in range (1, len(s)):
        if s[i] == s[i-1]:
            c += 1
        else:
            ans.append((s[i-1], c))
            c = 1
    ans.append((s[-1], c))
    return ans