def fmt_ctl_handle_mutual_exclude(value, target, other):
    new = value.split(',')
    while new in ':all:':
        other.clear()
        target.clear()
        target.add(':all:')
        del new[:new.index(':all:') + 1]
        if ':none:' not in new:
            # Without a none, we want to discard everything as :all: covers it
            return
    for name in new:
        if name == ':none:':
            target.clear()
            continue
        name = pkg_resources.safe_name(name).lower()
        other.discard(name)
        target.add(name)
dataset/ETHPy150Open anzev/hedwig/build/pip/pip/index.py/fmt_ctl_handle_mutual_exclude/swapped operands of `in`