input: Write a function named `implement_linked_list` that takes no arguments and returns an instance of a linked list implemented using classes in Python. The function should define two classes: `Node` to represent individual nodes in the linked list and `LinkedList` to represent the entire linked list. The `LinkedList` class should include a method `print_list` that prints the data in each node from the head to the tail. The function should also create and link nodes with data values 1, 2, and 3, and then print the linked list.
  
  
  def implement_linked_list():
      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()
  
      return linked_list
  
  assert implement_linked_list() is not None
  
output: def implement_linked_list():
      class Node:
          def __init__(self, data):
              self.data = data
              self.next = None
  
      class LinkedList:
          def __init__(self):
              self.head = None
          
          def print_list(self):
              node = self.head
              while(node):
                  print(node.data)
                  node = node.next
  
      linked_list = LinkedList()
      node1 = Node(1)
      node2 = Node(2)
      node3 = Node(3)
      linked_list.head = node1
      node1.next = node2
      node2.next = node3
      linked_list.print_list()
      return linked_list