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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 get_authority_key_identifier(self):
 """Return the AuthorityKeyIdentifier extension used in certificates signed by this CA."""


        try:
            ski = self.x509.extensions.get_extension_for_class(x509.SubjectKeyIdentifier)
        except x509.ExtensionNotFound:
            return x509.AuthorityKeyIdentifier.from_issuer_public_key(self.x509.public_key())
        else:
            return x509.AuthorityKeyIdentifier.from_issuer_subject_key_identifier(ski)