817 linked list components

def (self, head, G):
  """
  :type head: ListNode
  :type G: List[int]
  :rtype: int
  """
  pointer = head 
  count = 0
  conti = False
  Gset = set(G)
  while pointer != None:
      if pointer.val in Gset:
          conti = True
      else:
          if conti == True:
              count+=1
              conti = False
      pointer = pointer.next
  if conti == True:
      count+=1
  return count