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 __init__(self, schema_file: str):
        self._schema = artifact_utils.read_schema_file(schema_file)

        self._type_name, self._metric_fields = artifact_utils.parse_schema(
            self._schema)

        self._values = {}