class Node:
   def __init__(self, data):
      self.data = data
      self.next = None

class my_linked_list:
   def __init__(self):
      self.head = None
      self.last_node = None

   def add_value(self, my_data):
      if self.last_node is None:
         self.head = Node(my_data)
         self.last_node = self.head
      else:
         self.last_node.next = Node(my_data)
      self.last_node = self.last_node.next

   def print_it(self):
      curr = self.head
      while curr:
         print(curr.data)
         curr = curr.next

   def count_val(self, key):
      return self.count_helper_fun(self.head, key)

   def count_helper_fun(self, curr, key):
      if curr is None:
         return 0

      if curr.data == key:
         return 1 + self.count_helper_fun(curr.next, key)
      else:
         return self.count_helper_fun(curr.next, key)

my_instance = my_linked_list()
my_list = [56, 43, 70, 67, 89, 91, 70, 23, 46, 70]
for elem in my_list:
   my_instance.add_value(elem)
print("链表包含以下元素：")
my_instance.print_it()

key_val = int(input('输入数据项：'))
count_val = my_instance.count_val(key_val)
print('{0}在链表中出现了{1}次。'.format(key_val, count_val))

链表包含以下元素：
56
43
70
67
89
91
70
23
46
70
输入数据项：70

70在链表中出现了3次。