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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 check_validation(self, cert):
 """ Checks to see if a certificate has been validated, and if so, returns the ValidationPath used to validate it. :param cert: An asn1crypto.x509.Certificate object :return: None if not validated, or a certvalidator.path.ValidationPath object of the validation path """


        # CA certs are automatically trusted since they are from the trust list
        if self.certificate_registry.is_ca(cert) and cert.signature not in self._validate_map:
            self._validate_map[cert.signature] = ValidationPath(cert)

        return self._validate_map.get(cert.signature)