'Retrieves information about an HSM client.
:type client_arn: string
:param client_arn: The ARN of the client.
:type certificate_fingerprint: string
:param certificate_fingerprint: The certificate fingerprint.'

def describe_luna_client(self, client_arn=None, certificate_fingerprint=None):

    params = {}
    if (client_arn is not None):
        params['ClientArn'] = client_arn
    if (certificate_fingerprint is not None):
        params['CertificateFingerprint'] = certificate_fingerprint
    return self.make_request(action='DescribeLunaClient', body=json.dumps(params))
