(Python) How to access/use variable from different method in class? -

here's code

class circle(object):     def __init__(self, radius = 1):         self_radius = radius      def __str__(self):         return "circle radius {}".format(self_radius) 

i took teacher's slide, took integer (radius) when called (a = circle(25) -for example) return --circle radius 25-- when print it

the problem when that, instead getting it, got error saying self_radius not defined (in str method), question how use variable in different method it's origin?

thank you

qualify instance attributes self., not self_:

class circle(object):     def __init__(self, radius = 1):         self.radius = radius      def __str__(self):         return "circle radius {}".format(self.radius) 

if name variable self_radius, become local variable; not accessible method.