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 animate_cluster_allocation(data, observer, animation_velocity = 75, movie_fps = 1, save_movie = None):
        """!
        @brief Animates clustering process that is performed by EM algorithm.