class Solution:
def Merge(self, pHead1, pHead2):
# write code here
cur1,cur2=pHead1,pHead2
'''极端情况'''
if not cur1: return cur2
elif not cur2: return cur1
new_cur=ans=ListNode(0)
while cur1 and cur2:
if cur1.val<=cur2.val:
new_cur.next=cur1
cur1=cur1.next
else:
new_cur.next=cur2
cur2=cur2.next
new_cur=new_cur.next
new_cur.next = cur1 if cur1 else cur2
return ans.next