linked.py

class Node:

    def __init___(self,data=0,next=None):
        self.data = data
        self.next = next


class LinkedList:

    def __init__(self):
       self.head = None

    def push(self,data):
        new_node = Node()
        new_node.data  = data
        new_node.next = self.head
        self.head = new_node

    def print_list(self):
        current = self.head

        while(current):
            print current.data
            current=current.next

    def reverse(self):
        current = self.head
        prev = None
        nex = None
        while current:
            nex = current.next
            current.next = prev
            prev = current
            current = nex
        self.head = prev 


ll = LinkedList()
ll.push(1)
ll.push(2)
ll.push(3)
ll.push(4)

ll.print_list()

ll.reverse()
print 'Printing after reverse '
ll.print_list()