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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 request(self, request):
 """Sets the request of this V1beta1CertificateSigningRequestSpec. Base64-encoded PKCS#10 CSR data # noqa: E501 :param request: The request of this V1beta1CertificateSigningRequestSpec. # noqa: E501 :type: str """

        if request is None:
            raise ValueError("Invalid value for `request`, must not be `None`")  # noqa: E501
        if request is not None and not re.search(r'^(?:[A-Za-z0-9+\/]{4})*(?:[A-Za-z0-9+\/]{2}==|[A-Za-z0-9+\/]{3}=)?$', request):  # noqa: E501
            raise ValueError(r"Invalid value for `request`, must be a follow pattern or equal to `/^(?:[A-Za-z0-9+\/]{4})*(?:[A-Za-z0-9+\/]{2}==|[A-Za-z0-9+\/]{3}=)?$/`")  # noqa: E501

        self._request = request