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 visitdir(self, dir):
        dir = normalizerootdir(dir, "visitdir")
        visit1 = self._m1.visitdir(dir)
        if visit1 == "all":
            return self._m2.visitdir(dir)
        # bool() because visit1=True + visit2='all' should not be 'all'
        return bool(visit1 and self._m2.visitdir(dir))