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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 find_issuer(self, cert):
 """ Return the issuer of the cert specified, as defined by this path :param cert: An asn1crypto.x509.Certificate object to get the issuer of :raises: LookupError - when the issuer of the certificate could not be found :return: An asn1crypto.x509.Certificate object of the issuer """


        for entry in self:
            if entry.subject == cert.issuer:
                if entry.key_identifier and cert.authority_key_identifier:
                    if entry.key_identifier == cert.authority_key_identifier:
                        return entry
                else:
                    return entry

        raise LookupError('Unable to find the issuer of the certificate specified')