Python Classes without using def __init__(self)

Question

I am writing a series of text menus. With the class and sub class below it runs with no issues. But I am reviewing my coding and I am wondering....is it ok that I didn't use def __init__(self) in the classes? Should I have placed the data members in def __init__(Self): such as self.images = (), self.options =()? If I did that then I could not use the abc module for restrains, correct?

class BaseMenu(object):     __metaclass__ = abc.ABCMeta      @abc.abstractproperty     def options(self):         pass      @abc.abstractproperty     def menu_name(self):         pass      def display(self):         header = "FooBar YO"         term = getTerminalSize()         #sys.stdout.write("\x1b[2J\x1b[H")         print header.center(term, '*')         print self.menu_name.center(term, '+')         print "Please choose which option:"         for i in self.options:             print(                 str(self.options.index(i)+1) + ") "                 + i.__name__             )         value = int(raw_input("Please Choose: ")) - 1          self.options[value](self)  class Servers(BaseMenu):      menu_name = "Servers"     images = ()     foo = ()      def get_images(self):         if not self.images:             self.images = list_images.get_images()         for img in self.images:             print (                 str(self.images.index(img)+1) + ") "                 + "Name: %s\n    ID: %s" %                 (img.name, img.id)                 )      def get_foo(self):         if not self.foo:             self.foo = list_list.get_list()         for list in self.foo:             print "Name:", list.name             print "  ID:", list.id             print      def create_servers(self):          create_server.create(self)      options = (         get_images,         get_foo,         create_servers         ) 

Answer 1

Your code is perfectly fine. You don't have to have an __init__ method.

You can still use __init__, even with an ABC. All that the ABC meta tests for is if the names have been defined. Setting images in an __init__ does requires that you define a class attribute, but you can set that to None at first:

class Servers(BaseMenu):      menu_name = "Servers"     images = None     foo = None      def __init__(self):         self.images = list_images.get_images()         self.foo = list_list.get_list() 

Now you can set constraints on the ABC requiring that a images abstract property be available; the images = None class attribute will satisfy that constraint.