Here we ensure that the key student_id is part of the request. Although this validation works, it really does not belong in the function itself. Plus, perhaps there are other routes that use the exact same validation. So, let’s keep it DRY and abstract out any unnecessary logic with a decorator. The following @validate_json decorator will do the job:
This difference becomes most important when there are several independent ways of extending functionality. In some object-oriented programming languages, classes cannot be created at runtime, and it is typically not possible to predict, at design time, what combinations of extensions will be needed. This would mean that a new class would have to be made for every possible combination. By contrast, decorators are objects, created at runtime, and can be combined on a per-use basis. The I/O Streams implementations of both Java and the .NET Framework incorporate the decorator pattern.
Struggled to decide if this was a romance novel gone wrong, a story of a struggling artist, a chronicle on how & where to fish or a satirical farce. If it was any of these, did not work for me. 1/4 of the book is a primer on fishing, the rest bounces off the walls, trying to hit something, failing. What a romp through the absurd this novel is. Much time spent in cold creeks with nasty lures and mucky wading boots. The author kind of made the painter into a weeble wobble, he kept being punched at yet came back for more and more . The plots kind of remind me of a tv show I watched a few times. "Justified", a show about bubba dudes and dudesses in Harlen County Kentucky, the characters are portrayed as intelligent dummies, much like this novel. The Painter offers shallow, silly women, dare I say "bimbo's". The "painter" himself is a hapless "psychopath" who romps through life with no self check ability. He supposedly never means any of the harm he manages to encounter, just happens, right. Not to ruin a plot twist/surprise, but at one point a bullet is fired into the night, from a hand gun, with no light, landing hundreds of yards away and claiming it's prey. Haha, right, "I shot an arrow in the sky". It's a quick read, especially when you can Evelyn Woods it through all the tedious fishing. Yes, I know, the fishing, and the painting, were meant to be symbolic, but, it is only symbolic if the reader cares, and, this one did not !
Writing a class decorator is very similar to writing a function decorator. The only difference is that the decorator will receive a class and not a function as an argument. In fact, all the decorators you saw above will work as class decorators. When you are using them on a class instead of a function, their effect might not be what you want. In the following example, the @timer decorator is applied to a class:
Now we have our logit decorator in production, but when some parts of our application are considered critical, failure might be something that needs more immediate attention. Let’s say sometimes you want to just log to a file. Other times you want an email sent, so the problem is brought to your attention, and still keep a log for your own records. This is a case for using inheritence, but so far we’ve only seen functions being used to build decorators.
After 2.4a2 was released, in response to community reaction, Guido stated that he'd re-examine a community proposal, if the community could come up with a community consensus, a decent proposal, and an implementation. After an amazing number of posts, collecting a vast number of alternatives in the Python wiki , a community consensus emerged (below). Guido subsequently rejected  this alternate form, but added:
This book - The Painter - is a mockery of honesty and reality. Instead, this novel is a male fantasy. An emotional man, a painter, a fisherman, a loner, full of anger and rage, who doesn't hesitate to act on his feelings, defend his family with violence and sleeps with women like he is drinking water - not to mention he gives one woman 4 orgasms in one night. (insert your funny joke about me, the reviewer here)
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