A basic metaclass

Since metaclasses can modify any class attribute, you can do absolutely anything you wish. Before we continue with more advanced metaclasses, let’s create a metaclass that does the following:

1. Makes the class inherit int
2. Adds a lettuce attribute to the class
3. Changes the name of the class

First we create the metaclass. After that, we create a class both with and without the metaclass:

# The metaclass definition, note the inheritance of type instead
# of object
>>> class MetaSandwich(type):
...     # Notice how the __new__ method has the same arguments
...     # as the type function we used earlier?
...     def __new__(metaclass, name, bases, namespace):
...         name = 'SandwichCreatedByMeta'
...         bases = (int,) + bases
...         namespace['lettuce'] = 1
...         return type.__new__(metaclass, name, bases, namespace)

First, the regular Sandwich:

>>> class Sandwich...