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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 certs(self):
 """ List of the certificates contained in the structure """

        certstack = libcrypto.CMS_get1_certs(self.ptr)
        if certstack is None:
            raise CMSError("getting certs")
        return StackOfX509(ptr=certstack, disposable=True)