node_class.py

class Node:
    def __init__(self, element = None, next_node = None):
        self._element = element
        self._next = next_node

    def get_element(self):
        return self._element

    def get_next(self):
        return self._next

    def set_element(self, new_element):
        if self._element is None:
            self._element = new_element

    def set_next(self, new_next):
        old_next = self._next
        self._next = new_next
        return old_next
        
head = Node(5)
head = Node(10, head)
head = Node(25, head)
head = Node(15, head)
head = Node(20, head)

print('head', end='-->')
while head != None: 
  print( '| ' + str(head.get_element()) + ' |' , end='-->')
  head = head.get_next() 
print('None')