In the file you downloaded $($or opened$)$ at the beginning of this activity, add the method duplicate$($self$,$ item$)$ to the LinkedList class. This method will modify the original list such that if there is a node that has a value that is equal to item, that node will be duplicated $($do not duplicate the added nodes$).$ Note that you should be mutating the original link list; so you are not allowed to create new instances of the LinkedList class, you are only allowed to create Nodes and update links. Method returns None. Submit your code in the R$6$ Recitation Activity before the end of your recitation.

You can test your code with this small doctest:

$\text{'}\text{'}\text{'}$

$>>>$ lst $=$ LinkedList$()$

$>>>$ lst$.$add$(4)$

$>>>$ lst$.$add$(5)$

$>>>$ lst$.$add$(6)$

$>>>$ lst

Head:Node$(6)$

Tail:Node$(4)$

List:$6->5->4$

$>>>$ lst$.$duplicate$(6)$

$>>>$ lst

Head:Node$(6)$

Tail:Node$(4)$

List:$6->6->5->4$

$>>>$ lst$.$duplicate$(13)$

$>>>$ lst

Head:Node$(6)$

Tail:Node$(4)$

List:$6->6->5->4$

$>>>$ lst$.$add$(1)$

$>>>$ lst$.$duplicate$(6)$

$>>>$ lst

Head:Node$(1)$

Tail:Node$(4)$

List:$1->6->6->6->6->5->4$

$>>>$ lst$.$duplicate$(4)$

$>>>$ lst

Head:Node$(1)$

Tail:Node$(4)$

List:$1->6->6->6->6->5->4->4$

$\text{'}\text{'}\text{'}$

class Node:

def $\_\_$init$\_\_($self$,$ value$)$:

self.value $=$ value

self.next $=$ None

def $\_\_$str$\_\_($self$)$:

return "Node$(\{\})".$format$($self$.$value$)$

$\_\_$repr$\_\_=\_\_$str$\_\_$

class LinkedList:

def $\_\_$init$\_\_($self$)$:

self.head$=$None

self.tail$=$None

def $\_\_$str$\_\_($self$)$:

temp$=$self.head

out$=[]$

while temp:

out.append$($str$($temp$.$value$))$

temp$=$temp.next

out$=\text{'}->\text{'}.$join$($out$)$

return 'Head:$\{\}$

Tail:$\{\}$

List:$\{\}\text{'}.$format$($self$.$head,self.tail,out$)$

$\_\_$repr$\_\_=\_\_$str$\_\_$

def isEmpty$($self$)$:

return self.head$==$None

def $\_\_$len$\_\_($self$)$:

current$=$self.head

count$=0$

while current is not None:

count $+=1$

current $=$ current.next

return count

def add$($self$,$ value$)$:

newNode$=$Node$($value$)$

if self.isEmpty$()$:

self.head$=$newNode

self.tail$=$newNode

else:

newNode.next$=$self.head

self.head$=$newNode

def duplicate$($self$,$ item$)$:

# YOUR CODE STARTS HERE

pass