input: Write a function to implement a linked list using classes in Python. The function should create a `Node` class to represent a node in the linked list and a `LinkedList` class to represent the entire linked list. The `LinkedList` class should also have a method to print the linked list. Create instances of the linked list, nodes, and link the nodes accordingly. Finally, print the linked list to verify the implementation.
  
  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
  
  assert linked_list.head.data == 1
  assert linked_list.head.next.data == 2
  assert linked_list.head.next.next.data == 3
  assert linked_list.head.next.next.next == None
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
  