Bugfix: max candidates ranked > max_ranking_length

[ross-i]

If a RankProfile contains a ballot that ranks more than max_ranking_length candidates, some of the scoring functions can either crash or silently return incorrect results.

For example, consider a profile with a single ballot that ranks candidates A and B as tied for first. first_place_votes(profile, scoring_tie_convention='low') should return 0 for each candidate, but it instead returns 1. The score functions create a score_vector whose length is max_ranking_length, so, in this case, the score_vector is just [1], and when we have two candidates tied for first, taking min([1]) gives both 1. The correct behavior should be: the score_vector is [1, 0], so min yields 0.

To fix this, we should consider such profiles to be malformed, and insist that the user explicitly pass max_ranking_length.

The implementation: RankProfile now has a cached_property max_candidates_ranked, which, at initialization, is computed and compared against max_ranking_length. If max_candidates_ranked > max_ranking_length, RankProfile throws an error and suggests that the user either clean the profile to remove ties or explicitly pass max_ranking_length equal to whatever it computed max_candidates_ranked to be.

I updated the following tests:

1. utils - added a check that this error is raised
2. random dictator and boosted random dictator - these created profiles that are now considered malformed, so I added explicit passing of max_ranking_length.
3. test_rank_pp_ranking_length - this created a malformed profile (4 candidates ranked, but max_ranking_length implicitly equal to 3) and insisted that the result was a profile whose max_ranking_length is 3. I changed this to be a check for the error (same as utils essentially)

[peterrrock2]

This is looking great!

Small nit: I am trying to unify the doc string style accoss the repository. Can you modify the doc strings to look more like:

def  foo( arg1: str | None, arg2: int = 3) -> str:
    """
    Brief description (max 100 chars including indents)

    More details (max 100 chars per line, but as many lines as you would like)

    Example: 
        <Stuff goes here. This section is optional>

    Args:
        arg1 (str | None): description
        arg2 (int, optional): description. Defaults to 3.

    Returns:
        str: The string "baz"
    """
   ...

This is a mild modification of the Google-style doc string and adheres to the PEP 257 recommendation but with the line width modified to 100 chars rather than 80 (better for 16:9 screens IMO)

[ross-i]

This is looking great!

Small nit: I am trying to unify the doc string style accoss the repository. Can you modify the doc strings to look more like:

def  foo( arg1: str | None, arg2: int = 3) -> str:
    """
    Brief description (max 100 chars including indents)

    More details (max 100 chars per line, but as many lines as you would like)

    Example: 
        <Stuff goes here. This section is optional>

    Args:
        arg1 (str | None): description
        arg2 (int, optional): description. Defaults to 3.

    Returns:
        str: The string "baz"
    """
   ...

This is a mild modification of the Google-style doc string and adheres to the PEP 257 recommendation but with the line width modified to 100 chars rather than 80 (better for 16:9 screens IMO)

Done!