AttributeError: 'NoneType' object has no attribute 'labels'

Hello everyone,

I want to add relations to my csv file, but I keep on meeting this error,

** File "E:\Anaconda3\lib\site-packages\py2neo\", line 847, in init
Entity.init(self, (n[0], self, n[1]), properties)
File "E:\Anaconda3\lib\site-packages\py2neo\", line 553, in init
Walkable.init(self, iterable)
File "E:\Anaconda3\lib\site-packages\py2neo\", line 453, in init
_ = node.labels # ensure not stale
AttributeError: 'NoneType' object has no attribute 'labels'

Process finished with exit code 1**

I am following this tutorials. GitHub - jm199504/Financial-Knowledge-Graphs: 小型金融知识图谱构建流程
The related code is this:

matcher = NodeMatcher(graph)
for i in holder.values:
a = matcher.match("股票",TS代码=i[0]).first()
b = matcher.match("股东",TS代码=i[0])
for j in b:
#r = Relationship(j,'participant',a)

can anybody help me?