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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 init(self, ca, csr, **kwargs):
 """Create a signed certificate from a CSR and store it to the database. All parameters are passed on to :py:func:`Certificate.objects.sign_cert() <django_ca.managers.CertificateManager.sign_cert>`. """


        c = self.model(ca=ca)
        c.x509, csr = self.sign_cert(ca, csr, **kwargs)
        c.csr = csr.public_bytes(Encoding.PEM).decode('utf-8')
        c.save()

        post_issue_cert.send(sender=self.model, cert=c)
        return c