class whalrus.ScorerVeto(*args, count_abstention: bool = False, **kwargs)[source]

A Veto scorer for BallotVeto.

  • args – Cf. parent class.
  • count_abstention (bool) – If False (default), then an abstention grants no score at all. If True, then an abstention gives 0 point to each candidate (cf. below).
  • kwargs – Cf. parent class.


Typical usage:

>>> ScorerVeto(BallotVeto('a'), candidates={'a', 'b', 'c'}).scores_
{'a': -1, 'b': 0, 'c': 0}

Using the option count_abstention:

>>> ScorerVeto(BallotVeto(None), candidates={'a', 'b', 'c'}).scores_
>>> ScorerVeto(BallotVeto(None), candidates={'a', 'b', 'c'},
...                 count_abstention=True).scores_
{'a': 0, 'b': 0, 'c': 0}

The scores, given as floats. It is the same as scores_, but converted to floats.

Like all conversions to floats, it is advised to use this attribute for display purposes only. For computation, you should always use scores_, which usually manipulates fractions and therefore allows for exact computation.

Raises:ValueError – If the scores cannot be converted to floats.