'Hunts for a server HBA on the Dell backend by instance_name.
Instance_name is the same as the IQN or WWN specified in the
connector.
:param instance_name: Instance_name is a FC WWN or iSCSI IQN from
the connector.
:param ssn: Storage center to search.
:returns: Dell server HBA object.'

def _find_serverhba(self, instance_name, ssn):

    scserverhba = None
    pf = self._get_payload_filter()
    pf.append('scSerialNumber', ssn)
    pf.append('instanceName', instance_name)
    r = self.client.post('StorageCenter/ScServerHba/GetList', pf.payload)
    if self._check_result(r):
        scserverhba = self._first_result(r)
    return scserverhba
