Python Tricks: @classmethod vs @staticmethod vs “plain” methods

# @classmethod vs @staticmethod vs "plain" methods
# What's the difference?

class MyClass:
    def method(self):
        Instance methods need a class instance and
        can access the instance through `self`.
        return 'instance method called', self

    def classmethod(cls):
        Class methods don't need a class instance.
        They can't access the instance (self) but
        they have access to the class itself via `cls`.
        return 'class method called', cls

    def staticmethod():
        Static methods don't have access to `cls` or `self`.
        They work like regular functions but belong to
        the class's namespace.
        return 'static method called'

# All methods types can be
# called on a class instance:
>>> obj = MyClass()
>>> obj.method()
('instance method called', <MyClass instance at 0x1019381b8>)
>>> obj.classmethod()
('class method called', <class MyClass at 0x101a2f4c8>)
>>> obj.staticmethod()
'static method called'

# Calling instance methods fails
# if we only have the class object:
>>> MyClass.classmethod()
('class method called', <class MyClass at 0x101a2f4c8>)
>>> MyClass.staticmethod()
'static method called'
>>> MyClass.method()
    "unbound method method() must be called with MyClass "
    "instance as first argument (got nothing instead)"

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