from typing import List, Tuple


def topScorer(data: str) -> str | None:
    """Return the name(s) of the student(s) with the highest total score."""
    lines = [line for line in map(lambda line: line.strip(), data.split("\n")) if line]
    max_score: List[Tuple[str, int]] = []
    for line in lines:
        name, *scores = line.split(",")
        scores = list(map(int, scores))
        if not scores:
            max_score.append((name, 0))
        else:
            max_score.append((name, sum(scores)))
    max_score.sort(key=lambda x: x[1], reverse=True)
    if not max_score:
        return None
    names = [name for name, score in max_score if score == max_score[0][1]]
    return ",".join(names)


print("Testing topScorer()...", end="")
data = """\
Joe,10,20,30,40
Lauren,10,20,30
Ben,10,20,30,5
"""
assert topScorer(data) == "Joe"

data = """\
David,11,20,30
Austin,10,20,30,1
Lauren,50
"""
assert topScorer(data) == "David,Austin"

data = """\
Ping-Ya,100,80,90
"""
assert topScorer(data) == "Ping-Ya"

data = """\
Reyna,20,40,40
Ema,5,5,5,5,10
Ketandu,50,20,10,20
Tanya,80,20
Kate,70
"""
assert topScorer(data) == "Reyna,Ketandu,Tanya"

assert topScorer("") == None
print("Passed!")