Plz explain this python code?

Question

class Myclass:
def __init__(self,a=0,b=0):
self.a=a
self.b=b
@classmethod
def val(cls,value):
return cls(value*10)
obj=Myclass(1,2).val(3)
print(obj.a,obj.b)

Answer 1

Myclass(1, 2) return a Myclass instance with a = 1 and b = 2. Then use this instance to call a classmethod val(3), which returns cls(value*10).

cls refers to the constructor of the class, so it returns Myclass(value*10). In this case it's Myclass(30). Now obj is Myclass(30), which a = 30 and b = 0(default value).