def METHOD_NAME(self, mask):
    '''
    Start the accounting for a processors by a mask. Mask is
    a string, e.g.::
        0,1 -- first two CPUs
        0-4,6-10 -- CPUs from 0 to 4 and from 6 to 10
    Though the kernel has a procedure, that cleans up accounting,
    when it is not used, it is recommended to run deregister_mask()
    before process exit.
    '''
    self._register_mask('TASKSTATS_CMD_ATTR_REGISTER_CPUMASK', mask)