bool IBelongingsMatcher.IsBelongingTo(IBelongingsMatcher otherMatcher) => (otherMatcher as LeftParenthesis)?.Level == Level;
bool IBelongingsMatcher.IsBelongingTo(IBelongingsMatcher otherMatcher) => otherMatcher == this;
bool IBelongingsMatcher.IsBelongingTo(IBelongingsMatcher otherMatcher) => (otherMatcher as LeftParenthesis)?.Level == Level;
bool IBelongingsMatcher.IsBelongingTo(IBelongingsMatcher otherMatcher) => otherMatcher == this;