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 update_submodules(cls, location):
        if not os.path.exists(os.path.join(location, '.gitmodules')):
            return
        cls.run_command(
            ['submodule', 'update', '--init', '--recursive', '-q'],
            cwd=location,
        )