'Return LUN determined by the given arguments.'

def _find_lun(self, ldev, port, gid):

    result = self.run_raidcom('get', 'lun', '-port', '-'.join([port, gid]))
    match = re.search(('^%(port)s    +%(gid)s    +\\S+    +(?P<lun>\\d+)    +1    +%(ldev)s    ' % {'port': port, 'gid': gid, 'ldev': ldev}), result[1], re.M)
    if match:
        return match.group('lun')
    return None
