class triangle

from dataclasses import dataclass


class TriangleNotExistException(Exception):
    def __init__(self):
        super().__init__("Triangle with this sides doesn't exist")


@dataclass
class Triangle:
    """Класс треугольника"""
    a: int
    b: int
    c: int

    def __post_init__(self):
        if self.a + self.b <= self.c:
            raise TriangleNotExistException
        if self.b + self.c <= self.a:
            raise TriangleNotExistException
        if self.a + self.c <= self.b:
            raise TriangleNotExistException

    @property
    def ttype(self):
        if self.a == self.b == self.c:
            return "equilateral triangle"
        if self.a == self.b or self.c == self.a or self.b == self.c:
            return "isosceles triangle"
        return "normal triangle"


if __name__ == "__main__":
    tr1 = Triangle(2, 2, 3)
    print(tr1.ttype)
    tr2 = Triangle(1, 1, 100)