py2neo merge is returning None

Question

我有以下代码：

for t in set(tags):
new_tag = Node('Tag', name=t)
tag = graph.merge(new_tag, 'Tag', 'name')
rel = Relationship(tag, 'TAGGED', post)
graph.create(rel)

问题是graph.merge()返回None，但文档说如果没有找到匹配项，它会创建一个新节点。

这是我在执行graph.create(rel)时得到的错误：

File "/Users/hugovillalobos/Documents/Code/FlaskrGraphProject/FlaskrGraphVenv/lib/python3.7/site-packages/py2neo/internal/operations.py", line 134, in <genexpr>
for labels, nodes in _node_create_dict(n for n in subgraph.nodes if n.graph is None).items():
AttributeError: 'NoneType' object has no attribute 'graph'

Answer 1

合并后提交。然后创建关系。

Answer 2

您应该简单地使用：

tag = graph.merge(new_tag)