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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def from_dicts_by_key(cls, ds: dict, force_snake_case: bool=True, force_cast: bool=False, restrict: bool=True) -> TDict[T]: """From dict of dict to dict of instance :param ds: Dict of dict :param force_snake_case: Keys are transformed to snake case in order to compliant PEP8 if True :param force_cast: Cast forcibly if True :param restrict: Prohibit extra parameters if True :return: Dict of instance Usage: 'Tom' 'John' """

        return TDict({k: cls.from_dict(v,
                                       force_snake_case=force_snake_case,
                                       force_cast=force_cast,
                                       restrict=restrict) for k, v in ds.items()})