class Node:
    def __init__(self, cargo=None, next=None):
        self.cargo = cargo
        self.next = next
        def __str__(self):
            return str(self.cargo)

if __name__ == '__main__':
    node_1=Node(1)
    node_2=Node(2)
    node_3=Node(3)
    
    node_1.next=node_2
    node_2.next=node_3
    
    def printList(node):
        while node:
            print node.cargo,
            node = node.next
        print
    
    printList(node_1)