input: def implement_linked_list() -> str:
      """
      Write code in Python to implement a linked list using classes.
      
      Example:
      For the given code:
      
      # Creating a linked list 
      linked_list = LinkedList()
  
      # Creating the nodes
      node1 = Node(1)
      node2 = Node(2)
      node3 = Node(3)
  
      # Linking the nodes
      linked_list.head = node1
      node1.next = node2
      node2.next = node3
  
      # Printing the linked list
      linked_list.print_list()
      
      The output should be:
      
      1
      2
      3
      
      """
      return """class Node:
      \"\"\"Node class to represent the node in a linked list\"\"\"
      def __init__(self, data):
          self.data = data
          self.next = None
  
  
  class LinkedList:
      \"\"\"LinkedList class to represent the entire linked list\"\"\"
      def __init__(self):
          self.head = None
      
      def print_list(self):
          node = self.head
          while(node):
              print(node.data)
              node = node.next
  
  # Creating a linked list 
  linked_list = LinkedList()
  
  # Creating the nodes
  node1 = Node(1)
  node2 = Node(2)
  node3 = Node(3)
  
  # Linking the nodes
  linked_list.head = node1
  node1.next = node2
  node2.next = node3
  
  # Printing the linked list
  linked_list.print_list()"""
output:     
  class Node:
      """Node class to represent the node in a linked list"""
      def __init__(self, data):
          self.data = data
          self.next = None
  
  
  class LinkedList:
      """LinkedList class to represent the entire linked list"""
      def __init__(self):
          self.head = None
      
      def print_list(self):
          node = self.head
          while(node):
              print(node.data)
              node = node.next
  
  # Creating a linked list 
  linked_list = LinkedList()
  
  # Creating the nodes
  node1 = Node(1)
  node2 = Node(2)
  node3 = Node(3)
  
  # Linking the nodes
  linked_list.head = node1
  node1.next = node2
  node2.next = node3
  
  # Printing the linked list
  linked_list.print_list()"""