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Class variables, instance variables, local variables

Try out the following pieces of code 

#Instance variable
class A:
        def __init__(self):
                self.x = 22
                
a = A()
print a.x

#Local variable, only accessible inside init and vanishes afterwards
class A:
        
        def __init__(self):
                x = 22
                
a = A()
print a.x

#x is an instance variable
class A:
        
        x = 22
        def __init__(self):
                return None
                
a = A()
b = A()
a.x = 15
print a.x, b.x
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