    def matches(self) -> int:
        base_counts = Counter(self.read_bases)
        matches_forward = base_counts["."]
        matches_reverse = base_counts[","]
        return matches_forward + matches_reverse

    def match_ratio(self) -> float:
        try:
            return self.matches() / self.depth
        except ZeroDivisionError:
            return 0