Gee, the number of members here who are frantically trying to get their snakes to eat because they think they should be eating now is surprising. These are grown animals and know perfectly well what they need to do to survive. If the photo is a very recent one (last few days) it looks to me as though the animal is coming up to shed - it seems to have a pinkish tinge along the belly - a dead giveaway in Diamonds.
There has been a number of threads in recent days about snakes not feeding when the owners think they should. These snakes know far better than us when their physiologies are ready to kick up a notch, and at this time the seasons are changeable and it is risky for a snake to eat if, for example, a cold snap occurs. Although we keep them in managed environments, there are still cues outside their enclosures that affect their behaviour.
And PLEASE don't automatically reach to a live mouse or rat as an option to appease YOUR frustration. If the animal was raised on thawed/frozen food, it will continue to eat that food when it's good and ready.
Jamie