nifi Error(ExecuteScript): is not the most recent version of this flow file within this session

ExecuteScript(python):

当使用如下脚本，会报is not the most recent version of this FlowFile within this session。

flowFile = session.get()

session.putAttribute(flowFile, 'filename', 'executeScript')

if(flowFile != None):
    session.transfer(flowFile, REL_SUCCESS)
else:
    session.transfer(flowFile, REL_FAILURE)

修改第二行代码, 一定要赋值回一个flowFile变量：

flowFile = session.putAttribute(flowFile, 'filename', 'executeScript')