In general, functions in Python may also have side effects rather than just turning an input into an output. The print() function is a basic example of this: it returns None while having the side effect of outputting something to the console. However, to understand decorators, it is enough to think about functions as something that turns given arguments into a value.

Experience is more important than qualifications when attempting to find work. Working as a mate, or completing an apprenticeship, are both good ways to get this initial experience. If working independently as a self-employed person, experience is also necessary in order to be aware of the standard of work expected. A bad job will be easily noticed, and may lead to difficulty finding further work. When already working for a company, more in-depth courses can be completed in order to gain experience, which can sometimes lead to increases in salary. These courses could include:


In this snippet we have a class hierarchy with a SimpleMessage at the top. The SimpleMessage class has a constructor that accepts a content string as well as two methods: GetMessage; and, PrintMessage. Down the hierarchy we have three subclasses: ExcitedMessage; QuizzicalMessage; and, ExcitedAndQuizzicalMessage. The only difference in the subclasses is that they override the SimpleMessage constructor to change the content string and append various exclamations. When we instantiate various message objects, using the same content string, and iterate over them, each has their own unique output.
Experience is more important than qualifications when attempting to find work. Working as a mate, or completing an apprenticeship, are both good ways to get this initial experience. If working independently as a self-employed person, experience is also necessary in order to be aware of the standard of work expected. A bad job will be easily noticed, and may lead to difficulty finding further work. When already working for a company, more in-depth courses can be completed in order to gain experience, which can sometimes lead to increases in salary. These courses could include:

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.
Concrete Decorator: Here we have two concrete decorators, ExcitedMessageDecorator and QuizzicalMessageDecorator, each of which descends from the abstract MessageDecorator class. However, these decorators do have special behavior in that they override the GetMessage and PrintMessage behaviors and enhance them by calling the base version from MessageDecorator (which in turn delegates to the relevant IMessage object) and then appending exclamations.
Color, made up of hue, saturation, and value, dispersed over a surface is the essence of painting, just as pitch and rhythm are the essence of music. Color is highly subjective, but has observable psychological effects, although these can differ from one culture to the next. Black is associated with mourning in the West, but in the East, white is. Some painters, theoreticians, writers and scientists, including Goethe,[3] Kandinsky,[4] and Newton,[5] have written their own color theory.
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