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:
Painters prepare surfaces of building and other structures and then apply paint by means of brushes, rollers or sprayers. They work with varnish, enamels, lacquer and other materials. They may also paint interior rooms or cover walls with paper, fabrics, vinyls or other materials (paperhanger). They must be able to mix paints as well as do sandblasting and waterblasting.
Aerosol paint (also called spray paint) is a type of paint that comes in a sealed pressurized container and is released in a fine spray mist when depressing a valve button. A form of spray painting, aerosol paint leaves a smooth, evenly coated surface. Standard sized cans are portable, inexpensive and easy to store. Aerosol primer can be applied directly to bare metal and many plastics.
Modern and Contemporary Art has moved away from the historic value of craft and documentation in favour of concept, leading some to say, in the 1960s, that painting as a serious art form is dead.[clarification needed] This has not deterred the majority of living painters from continuing to practice painting either as whole or part of their work. The vitality and versatility of painting in the 21st century defies the previous "declarations" of its demise. In an epoch characterized by the idea of pluralism, there is no consensus as to a representative style of the age. Artists continue to make important works of art in a wide variety of styles and aesthetic temperaments—their merits are left to the public and the marketplace to judge.
Overall unfamiliarity with the concept. For people who have a passing acquaintance with algebra (or even basic arithmetic) or have used at least one other programming language, much of Python is intuitive. Very few people will have had any experience with the decorator concept before encountering it in Python. There's just no strong preexisting meme that captures the concept.
John Mansell Smith has been a self-employed painter & decorator for four years. He explains what it’s like to run your own business. “I became a self-employed painter & decorator when I took early retirement from my professional job in London, where I was employed as a Principal Building Surveyor. When I retired, I needed some additional income to supplement my pension, and having been in the building industry I was fully aware of the standard and quality which would be required to produce work to a professional standard. For a typical day at work, I usually arrive at the job at 8.30 am, and then depending on the sort of work I am doing it will vary a great deal. I could be undertaking external decorations or internal decorations, but in each case it would require covering and protecting the client's furniture, preparation of surfaces, washing down the walls, painting, wallpapering, cleaning up, etc. I try to leave at about 4.30 pm, but this may vary depending on the stage that I have reached with the job. In terms of likes and dislikes, I don’t enjoy working outside in poor weather, although I try to plan my workload to avoid this. However, I do like the freedom of being my own boss and getting complimented on a good job. If you wanted to be a painter and decorator, you would have to decide whether you wish to work for a company with the benefits such as holiday pay, but with the constraints of not being your own boss, or working for yourself with the freedom this gives but also the uncertainty of workload. As a self-employed person I can charge about £15 per hour for work that I do on an hourly rate, or I base any calculations on this rate when I am producing an estimate for a client. In attempting to find work, I would try the job centre, trade journals, large decorating companies, the internet and building training boards. To do the job you need to be a clean, neat worker with an eye for detail. The job you produce is the final result that the client will see, so it is vital that you can produce a finished job that you would be happy to have in your own home.
Some commonly used decorators that are even built-ins in Python are @classmethod, @staticmethod, and @property. The @classmethod and @staticmethod decorators are used to define methods inside a class namespace that are not connected to a particular instance of that class. The @property decorator is used to customize getters and setters for class attributes. Expand the box below for an example using these decorators.
Syntactic constraints. Python is a syntactically simple language with fairly strong constraints on what can and can't be done without "messing things up" (both visually and with regards to the language parser). There's no obvious way to structure this information so that people new to the concept will think, "Oh yeah, I know what you're doing." The best that seems possible is to keep new users from creating a wildly incorrect mental model of what the syntax means.
Painting is an important form in the visual arts, bringing in elements such as drawing, gesture (as in gestural painting), composition, narration (as in narrative art), or abstraction (as in abstract art). Paintings can be naturalistic and representational (as in a still life or landscape painting), photographic, abstract, narrative, symbolistic (as in Symbolist art), emotive (as in Expressionism), or political in nature (as in Artivism).