What do init and self do in Python duplicate

Question

During my Python lectures, I've come across a doubt and stuck in that and I'm not really sure how to handle.

def method(self, blah):
    def __init__(?):
        ....
    ....

What is the function of self? and is it required?

The __init__ method's purpose is what? Why is it required? (etc.)

Though I don't know much, I believe they could be OOP constructs.