error "No value for argument 'change' in unbound method call" for ''x.'' in final line. __init__ method not used

Question

class a:
    app = [2,3,5,21,24,28,35]
    web = [1,9,22,46]
    x = min(app,web);y = max(app,web) 
    a = len(x)
    w = len(y)
    c=0;d=0
    def till_xbig(self,i ,j ,change):
        while self.x[i] < self.y[j] :
            self.c+=1
            if i<self.a-1 and self.c <self.a:
                i+=1
            else:
                break

        change += 1
        self.till_ybig(i,j,change)

    def till_ybig(self,i,j,change):
        while self.y[j] < self.x[i] :
            self.d+=1
            if j<self.w-1 and self.d<self.w:
                j+=1
            else:
                break
        change += 1
        if i == self.a-1 and j == self.w-1:   return change
        self.till_xbig(i,j,change)

x = a
print(x.till_xbig(0,0,0))

**i have assigned class instance to x but still i am getting this "method unbound call" error why is "self" taking up first 0 and the reason why change is not receiving that third 0 as arguement. how to avoid such mistake? **

Answer 1

Where x = a means assigning x as a class.

In your case, should use x = a(). It assigns x as a a instance.

>>> x = a
>>> x
>>> <class '__main__.a'>

>>> x = a()
>>> x
>>> <__main__.a object at 0x00000215D6FBEF20>