876. middle of the linked list

def (self, head):
  """
  :type head: ListNode
  :rtype: ListNode
    """
  pt = head
  count = 0
  while pt != None: 
      pt = pt.next
      count+=1
  mid = count / 2 if count%2 == 0 else (count-1)/2
  pa = head
  countTwo = 0
  while countTwo < mid:
      pa = pa.next
      countTwo+=1
  return pa

def middleNodeQuicker(self,head):  
    pfast = head
    pslow = head
    while pfast != None and pfast.next != None:
        pfast = pfast.next.next
        pslow = pslow.next
    return pslow