Using Python and the code give below add the following method to the Unorderedlist.

replace_element:

Given a position i, and a new_value, the method replaces the value of the element at position i, where position 0 corresponds to the head of the list with the new_value.

Implement a main function in the modified UnorderedList.py to demonstrate that the new method works as expected.

Unorderedlist:

from Node import Node class UnorderedList:   def __init__(self): self.head = None    def is_empty(self): return self.head == None    def add(self, item): # Create a node using item as its data  temp = Node(item) # make the next reference of the new node refer to the head  # of the list  temp.set_next(self.head) # modify the list head so that it references the new node  self.head = temp '''  Returns the size of the list  '''  def size(self): # start at the head of the list  current = self.head count = 0 # Traverse the list one element at a time. We know  # we reached the end when the next reference is None  while current != None: count = count + 1 current = current.get_next() return count '''  Search for an item in the list. Returns True if found, False otherise.  '''  def search(self,item): current = self.head found = False  # As long as the element is not found and we haven't  # reached the end of the list  while current != None and not found: if current.get_data() == item: found = True  else: # go to the next element  current = current.get_next() return found '''  Remove the first occurrence of item from the list.  '''  def remove(self, item): # keep track of current and previous elements  current = self.head previous = None  found = False  # traverse the list  while current != None and not found: # if we have a match, stop  if current.get_data() == item: found = True  # otherwise advance current and next references  else: previous = current current = current.get_next() # the element to be deleted is the head of the list  if found: if previous == None: self.head = current.get_next() # the element to be deleted is not the head  else: previous.set_next(current.get_next()) def print_list(self): result = "["  node = self.head if node != None: result += str(node.data) node = node.next while node: result += ", " + str(node.data) node = node.next result += "]"  print (result) return result def main(): # create a list and add some elements to it  aList = UnorderedList() print("Adding 3, 5, 8, and 11 to the list.") aList.add(3) aList.add(5) aList.add(8) # 11 is the head of the list  aList.add(11) print("List size:", aList.size()) print("Is 5 in the list? ", aList.search(5)) print("Removing 5 from the list.") aList.remove(5) print("Is 5 in the list? ", aList.search(5)) print("List size:", aList.size()) print("Removing 3 from the list.") aList.remove(3) print("List size:", aList.size()) aList.print_list() if __name__ == "__main__": main() 

NODE:

class Node:   def __init__(self, init_data): self.data = init_data self.next = None   def get_data(self): return self.data   def get_next(self): return self.next   def set_data(self, new_data): self.data = new_data   def set_next(self, new_next): self.next = new_next