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 permutation_subjects(y):
    """Permute class labels of Contextual Disorder dataset.
    """
    y_perm = np.random.randint(0, 2, len(y)/2)
    y_perm = np.concatenate((y_perm, np.logical_not(y_perm).astype(int)))
    return y_perm