def _tap(tap, runas=None):
    '''
    Add unofficial GitHub repos to the list of formulas that brew tracks,
    updates, and installs from.
    '''
    if _list_taps() in tap:
        return True

    cmd = 'brew tap {0}'.format(tap)
    if _call_brew(cmd)['retcode']:
        log.error('Failed to tap "{0}"'.format(tap))
        return False

    return True
dataset/ETHPy150Open saltstack/salt/salt/modules/mac_brew.py/_tap/swapped operands of `in`