# Definition for singly-linked list.
class ListNode:
    def __init__(self, val=0, next=None):
        self.val = val
        self.next = next
class Solution:
    def reverseKGroup(self, head: ListNode, k: int) -> ListNode:
        dummy = ListNode(0)
        dummy.next = head
        
        
        def reversell(head):
            
            if not head or head.next==None:
                head
            temp = head.next
            #### to complete ####
            

                
            
# Definition for singly-linked list.
class ListNode:
    def __init__(self, val=0, next=None):
        self.val = val
        self.next = next
class Solution:
    def reverseKGroup(self, head: ListNode, k: int) -> ListNode:
        dummy = ListNode(0)
        dummy.next = head
        
        
        def reversell(head):
            
            if not head or head.next==None:
                head
            temp = head.next
            #### to complete ####
            

                
            
# Definition for singly-linked list. #### to complete ####