Removes tag with the given ``name``.

        :param name: name of the tag to be removed
        :param user: full username, i.e.: "Joe Doe <joe.doe@example.com>"
        :param message: message of the tag's removal commit
        :param date: date of tag's removal commit

        :raises TagDoesNotExistError: if tag with given name does not exists

def remove_tag(self, name, user, message=None, date=None):
        """
        Removes tag with the given ``name``.

        :param name: name of the tag to be removed
        :param user: full username, i.e.: "Joe Doe <joe.doe@example.com>"
        :param message: message of the tag's removal commit
        :param date: date of tag's removal commit

        :raises TagDoesNotExistError: if tag with given name does not exists
        """
        if name not in self.tags:
            raise TagDoesNotExistError("Tag %s does not exist" % name)
        if message is None:
            message = "Removed tag %s" % name
        if date is None:
            date = datetime.datetime.now().ctime()
        local = False

        try:
            self._repo.tag(name, nullid, message, local, user, date)
            self.tags = self._get_tags()
        except Abort, e:
            raise RepositoryError(e.message)