"""
Minimal stub for `problem` module used in trace_back tests. Provides lightweight
constructs used by tests so import-time failures do not occur during collection.
"""
from typing import Any, List


class Problem:
    def __init__(self, text: str):
        self.text = text
        self.goal = None

    @classmethod
    def from_txt(cls, txt: str) -> 'Problem':
        return cls(txt)


class Definition:
    @classmethod
    def from_txt_file(cls, path: str, to_dict: bool = False):
        return {}


class Theorem:
    @classmethod
    def from_txt_file(cls, path: str, to_dict: bool = False):
        return {}


class Dependency:
    def __init__(self, *args, **kwargs):
        pass


__all__ = ["Problem", "Definition", "Theorem", "Dependency"]