def create_default_groups(self):
        for group in self.groups:
            group = group.replace(" ", "_").lower()
            self[group] = NamedRequirements(group)
def show_clusters(clusters, sample, covariances, means, figure=None, display=True):
        """!
        @brief Draws clusters and in case of two-dimensional dataset draws their ellipses.
        @details Allocated figure by this method should be closed using `close()` method of this visualizer.