def __call__(self, distribution):
    '\n        Apply the distribution statistic function; must be implemented by subclasses.\n\n        Subclasses sould be called with a Distribution as argument, return will be a\n        dictionary, with Pref objects as values\n        '
    raise NotImplementedError
Apply the distribution statistic function; must be implemented by subclasses.

Subclasses sould be called with a Distribution as argument, return will be a
dictionary, with Pref objects as values
def __call__(self, distribution):
    '\n        Apply the distribution statistic function; must be implemented by subclasses.\n\n        Subclasses sould be called with a Distribution as argument, return will be a\n        dictionary, with Pref objects as values\n        '
    raise NotImplementedError