the self keyword

What does instance really mean?

When python goes to create the Human class in the first class example, it allocates a new generic object that all classes inherit from. This defines some basic behavior by default, but now we don't have the Human class we are working with, we have this new object to work on. That is what self represents in each method

class Brain:
	iq: int
	def __init__(self, iq: int) -> None:
		self.iq = iq

	def compareIq(self, other) -> None:
		print(f"Comparing to {other}")
		return self.iq - other.iq
		
class Human:
	name: str    # we can specify what type we expect instance variables to be
    def __init__(self, name, iq): # type decorators are optional, but encouraged
        self.name = name       # note that `self.name` and `name` are two diffirent objects
		self.brain = Brain(iq) # you can have instance variables of other classes

    def say(self, msg):
        print("{name}: {message}".format(name=self.name, message=msg))

    def sing(self):
        return "yo... yo... microphone check... one two... one two..."

	def smarterThan(self, other) -> bool:
		return self.brain.compareIq(other.brain) > 0

	def changeName(self, name):
		self.name = name


bob = Human("Bob", 100) 

bob.say("hi!")     
bob.sing()         

bob.changeName("Billy")
bob.say("I go by Billy now")

james = Human("James", 150)
james.say("Hi Billy")

print(james.smarterThan(bob)) # => True

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