三角形の種類の判定

問題

三角形の種類を判定する関数triangle_shape()を完成させて、正常終了するようにしてください。

from enum import Enum, auto
from itertools import permutations
from math import inf, isinf, isnan, nan


class TriShape(Enum):
    Nontriangular = auto()  # 非三角形
    Equilateral = auto()  # 正三角形
    Isosceles = auto()  # 二等辺三角形
    Scalene = auto()  # 一般の三角形


def triangle_shape(a1, a2, a3) -> TriShape:
    ここを修正
    return TriShape.Scalene


if __name__ == "__main__":
    params = [
        (3, 4, "5", TriShape.Nontriangular),
        (None, 1, 1, TriShape.Nontriangular),
        (nan, 1, 1, TriShape.Nontriangular),
        (inf, 1, 1, TriShape.Nontriangular),
        (inf, inf, 1, TriShape.Nontriangular),
        (-1, 1, 1, TriShape.Nontriangular),
        (0, 0, 0, TriShape.Nontriangular),
        (0, 1, 1, TriShape.Nontriangular),
        (2, 1, 1, TriShape.Nontriangular),
        (1, 2, 3, TriShape.Nontriangular),
        (1, 1, 1, TriShape.Equilateral),
        (1e-2, 1, 1, TriShape.Isosceles),
        (1e-20, 1, 1, TriShape.Isosceles),
        (3, 4, 5, TriShape.Scalene),
    ]
    for param in params:
        expected = param[3]
        for args in set(permutations(param[:3])):
            actual = triangle_shape(*args)
            assert actual == expected, f"{args} {actual}"