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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 certificate(self, certificate):
 """ Sets the certificate of this V1beta1CertificateSigningRequestStatus. If request was approved, the controller will place the issued certificate here. :param certificate: The certificate of this V1beta1CertificateSigningRequestStatus. :type: str """

        if certificate is not None and not re.search('^(?:[A-Za-z0-9+\/]{4})*(?:[A-Za-z0-9+\/]{2}==|[A-Za-z0-9+\/]{3}=)?$', certificate):
            raise ValueError("Invalid value for `certificate`, must be a follow pattern or equal to `/^(?:[A-Za-z0-9+\/]{4})*(?:[A-Za-z0-9+\/]{2}==|[A-Za-z0-9+\/]{3}=)?$/`")

        self._certificate = certificate