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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 server_version(self):
 """Attempts to determine the version of Vault that a server is running. Some actions will change on older Vault deployments."""

        health_url = "%s/v1/sys/health" % self.vault_addr
        resp = self.session.request('get', health_url, **self._kwargs)
        if resp.status_code == 200 or resp.status_code == 429:
            blob = resp.json()
            if 'version' in blob:
                return blob['version']
        else:
            raise aomi.exceptions.VaultProblem('Health check failed')

        return None