class ClassTest:

def instance_method(self):

print(f"Called instance_method of {self}")

@classmethod

def class_method(cls):

print(f"Called class_method of {cls}")

@staticmethod

def static_method():

print(f"Called static_method. We don't get any object or class info here.")

instance = ClassTest()

instance.instance_method()

ClassTest.class_method()

ClassTest.static_method()

# -- What are they used for? --

# Instance methods are used for most things. When you want to produce an action that uses the data stored in an object.

# Static methods are used to just place a method inside a class because you feel it belongs there (i.e. for code organisation, mostly!)

# Class methods are often used as factories.

class Book:

TYPES = ("hardcover", "paperback")

def __init__(self, name, book_type, weight):

self.name = name

self.book_type = book_type

self.weight = weight

def __repr__(self):

return f"<Book {self.name}, {self.book_type}, weighing {self.weight}g>"

@classmethod

def hardcover(cls, name, page_weight):

return cls(name, cls.TYPES[0], page_weight + 100)

@classmethod

def paperback(cls, name, page_weight):

return cls(name, cls.TYPES[1], page_weight)

heavy = Book.hardcover("Harry Potter", 1500)

light = Book.paperback("Python 101", 600)

print(heavy)

print(light)