def __add__(self, other):
        if isinstance(other, MessageSet):
            ranges = self.ranges + other.ranges
            return MessageSet(ranges)
        else:
            res = MessageSet(self.ranges)
            try:
                res.add(*other)
            except __HOLE__:
                res.add(other)
            return res
dataset/ETHPy150Open nlloyd/SubliminalCollaborator/libs/twisted/mail/imap4.py/MessageSet.__add__