22- the list penultimate k nodes

Title: Enter a linked list, the linked list output penultimate node k.

def find_Kth_tail(head,k):
    if not head or k<1:
        return None
    
    p = head
    q = head
    cnt = 0
    while p:
        cnt+=1
        p=p.next
    if k>cnt:
        return None
    p = head
    for i in range(k):
        p = p.next

    while p:
        p = p.next
        q = q.next

    return q.data

Note:

Use two pointers, a pointer k go first step, then two hands while walking, a current list pointer reaches the end of time, after a pointer is the penultimate k nodes. This interpretation of the data input to be noted that the question of whether the first node is empty, if k is greater than 0, and k is smaller than the total length of the list.