test.py

    def _pick_by_class_ref(self, cls_ref, comparision_type="exact"):
        func = getattr(self, comparision_type)
        try:
            _refs = self.db["key"][cls_ref]
        except KeyError:
            return []
        else:
            _item = self.db["info"][_refs[0]]
            _level = _item["level"]
            if comparision_type != "better":
                if _item["method"]:
                    res = [(_item["method"], _refs[0])]
                else:
                    res = []
            else:
                res = []

            for ref in _refs[1:]:
                item = self.db["info"][ref]
                res.append((item["method"], ref))
                if func(_level, item["level"]):
                    _level = item["level"]
            for ref, _dic in self.db["info"].items():
                if ref in _refs:
                    continue
                elif func(_level, _dic["level"]):
                    if _dic["method"]:
                        _val = (_dic["method"], ref)
                        if _val not in res:
                            res.append(_val)
            return res