In a Python LinkedList, why use sentinel nodes instead of a None or Null

What is the difference between these constructors for a LinkedList, why is one better or worse than the other?

class Node:
    def __init__(self, data):
        self.data = data
        self.next = None

class Singly_Linked_List:
    def __init__(self):
        self.head = None

versus:

class Singly_Linked_List:
    def __init__(self):
        self.head = Node(0)

Does this affect how the SLL or DLL would be implemented for the addAtIndex, removeAtIndex functions for example?