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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 is_valid(obj: JSGValidateable, log: Optional[Union[TextIO, Logger]] = None) -> bool: """ Determine whether obj is valid :param obj: Object to validate :param log: Logger to record validation failures. If absent, no information is recorded """

    return obj._is_valid(log)