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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 cert_from_instance(instance):
 """ Find certificates that are part of an instance :param instance: An instance :return: possible empty list of certificates """

    if instance.signature:
        if instance.signature.key_info:
            return cert_from_key_info(instance.signature.key_info,
                                      ignore_age=True)
    return []