Literary license :-)

Easier to rhyme Yes and No than True and False


>John,
>
>Are you sure it's set "No"? Could i be "Off" instead?
>
>TIA
>>
>>Here's the challenge:
>>
>>By default, I'm set "No"
>>But you probably should know
>>That unless you set me "Yes"
>>Your numbers will be a mess
>>
>>Name that Property!