A good idea's occurred to me — say yes? No! (1,4)

I believe the answer is:

i know

I'm a little stuck... Click here to teach me more about this clue!

'a good idea's occurred to me' is the definition.
('I know' might be said before giving a suggestion)

I don't understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for i know that I've seen before include "That's an idea" , "Here's an idea" .)

I've seen this clue in The Guardian.

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