def __init__(self, package, version):
        """Construct a new requirement.

        :param package: the package name.
        :param version: a semver compatible version specification.
        """
        self.package = package
        self.version = version
        if self.version and not re.match(r"[<=>~]", version[:2]):
            self.version = "=={}".format(self.version)
def _get_snapshot_status(self, snapshot_id):
        resp, body = self.get_snapshot(snapshot_id)
        status = body['status']
        # NOTE(afazekas): snapshot can reach an "error"
        # state in a "normal" lifecycle
        if (status == 'error'):
            raise exceptions.SnapshotBuildErrorException(
                snapshot_id=snapshot_id)

        return status