def __init__(self, groups=None):
        super(GroupedRequirements, self).__init__(NamedRequirements)
        self.groups = groups or self.default_groups
        self.filename = None
        self.create_default_groups()
def notify(self, means, covariances, clusters):
        """!
        @brief This method is used by the algorithm to notify observer about changes where the algorithm
                should provide new values: means, covariances and allocated clusters.