class Point:
def __init__(self, x, y):
self.x = x
self.y = y
self.next = None
def append(self, point):
self.next = point
a = Point(2, 3)
b = Point(5, 7)
a.append(b)
print a.next.x
c = Point(10, 15)
b.append(c)
print a.next.next.x
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