Sum of the alternate nodes of linked list in python

Python program for Sum of the alternate nodes of linked list. Here problem description and explanation.

#  Python 3 program for
#  Sum of the alternate nodes of linked list

#  Linked list node
class LinkNode :
	def __init__(self, data) :
		self.data = data
		self.next = None
	

class SingleLL :
	def __init__(self) :
		self.head = None
	
	#  Add new node at the end of linked list
	def insert(self, value) :
		#  Create a node
		node = LinkNode(value)
		if (self.head == None) :
			self.head = node
		else :
			temp = self.head
			#  Find last node
			while (temp.next != None) :
				#  Visit to next node
				temp = temp.next
			
			#  Add node at last position
			temp.next = node
		
	
	#  Display all Linked List elements
	def display(self) :
		if (self.head != None) :
			temp = self.head
			while (temp != None) :
				#  Display node value
				print("  ", temp.data, end = "")
				#  Visit to next node
				temp = temp.next
			
		else :
			print("Empty Linked list")
		
	
	#  Sum of all alternate nodes of linked list
	def sumAlternateNode(self) :
		#  Get first node
		temp = self.head
		sum = 0
		#  Iterate the elements of linked list, 
		#  And sum of all alternate element.
		while (temp != None) :
			#  Sum node value
			sum += temp.data
			if (temp.next != None) :
				#  Visit to next second node
				temp = temp.next.next
			else :
				#  When no alternate node
				#  Like break
				temp = None
			
		
		#  Display result
		print("\n Sum of all alternate nodes : ", sum)
	

def main() :
	sll = SingleLL()
	#  Linked list
	#  6 → 2 → 1 → 4 → 3 → 3 → 4 → 8 → NULL
	sll.insert(6)
	sll.insert(2)
	sll.insert(1)
	sll.insert(4)
	sll.insert(3)
	sll.insert(3)
	sll.insert(4)
	sll.insert(8)
	print(" Linked List")
	sll.display()
	sll.sumAlternateNode()

if __name__ == "__main__": main()

Output

 Linked List
   6   2   1   4   3   3   4   8
 Sum of all alternate nodes :  14