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 modify(self, pmtu):
        self.pmtu = pmtu
        self._test.vapi.ip_path_mtu_update(pmtu={'nh': self.nh,
                                                 'table_id': self.table_id,
                                                 'path_mtu': self.pmtu})
        return self