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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_optional_dicts_by_key(cls, ds: Optional[dict], force_snake_case=True, force_cast: bool=False, restrict: bool=True) -> TOption[TDict[T]]: """From dict of dict to optional 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: True {} """

        return TOption(cls.from_dicts_by_key(ds,
                                             force_snake_case=force_snake_case,
                                             force_cast=force_cast,
                                             restrict=restrict) if ds is not None else None)