inserting in a linked list between two data node

1class Node:
2   def __init__(self, dataval=None):
3      self.dataval = dataval
4      self.nextval = None
5class SLinkedList:
6   def __init__(self):
7      self.headval = None
8
9# Function to add node
10   def Inbetween(self,middle_node,newdata):
11      if middle_node is None:
12         print("The mentioned node is absent")
13         return
14
15      NewNode = Node(newdata)
16      NewNode.nextval = middle_node.nextval
17      middle_node.nextval = NewNode
18
19# Print the linked list
20   def listprint(self):
21      printval = self.headval
22      while printval is not None:
23         print (printval.dataval)
24         printval = printval.nextval
25
26list = SLinkedList()
27list.headval = Node("Mon")
28e2 = Node("Tue")
29e3 = Node("Thu")
30
31list.headval.nextval = e2
32e2.nextval = e3
33
34list.Inbetween(list.headval.nextval,"Fri")
35
36list.listprint()