class Node:
 
    def __init__(self, value=None):
        self.value = value
        self.next = self
 
    def Next(self):
        return self.next
 
    def SetNext(self, node):
        self.next = node
 
    def Value(self):
        return self.value
 
    def AddAfter(self, node):
        node.SetNext(self.Next())
        self.next = node
        return node
 
    def AddBefore(self, node):
        curr = self
        while curr.Next() != self:
            curr = curr.Next()
        curr.AddAfter(node)
        return node
 
    def __str__(self):
        return str(self.value)
 
node = Node()
node1 = node.AddAfter(Node(1))
node2 = node1.AddAfter(Node(2))
node3 = node2.AddBefore(Node(3))
 
print(node.Next(), node.Next().Next(), node.Next().Next().Next())

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