swap-nodes-in-pairs

Given a linked list, swap every two adjacent nodes and return its head.

Example:

Given 1->2->3->4, you should return the list as 2->1->4->3.
Note:

Your algorithm should use only constant extra space.
You may not modify the values in the list's nodes, only nodes itself may be changed.

My code:
# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution:
    def swapPairs(self, head):
        """
        :type head: ListNode
        :rtype: ListNode
        """
        if head==None:
            return None
        count=0
        result=[]
        while head.next!=None:
            if count%2==0:
                tmp_Value=head.val
            else:
                result.append(head.val)
                result.append(tmp_Value)
            head=head.next
            count+=1
        if count%2==0:
            tmp_Value=head.val
            result.append(tmp_Value)
        else:
            result.append(head.val)
            result.append(tmp_Value)
        return result
        
Solution:
https://leetcode.com/problems/swap-nodes-in-pairs/