Return the minions found by looking via pillar

def mmatch(expr, delimiter, greedy, opts=None):
    '''
    Return the minions found by looking via pillar
    '''
    if not opts:
        opts = __opts__

    ckminions = salt.utils.minions.CkMinions(opts)
    return ckminions._check_compound_minions(expr, delimiter, greedy,
                                             pillar_exact=True)