can't run traversal "unsanitized"

[Smaugon]

It confuses me so much. I have installed the latest version of python joern, and I use the following traversal
getArguments('memcpy', '2')
.sideEffect{ paramName = '.len.' }
.filter{ it.code.matches(paramName) }
.unsanitized{ it.isCheck( paramName ) }
.params( paramName )
It is showed on https://joern.readthedocs.io/en/latest/querying.html as an example, but I failed.
I have checked the code over and over, but I have no clue.
Please tell me how to solve it!

[Smaugon]

I wish you could check it again. The param "sanitizer" of the closure "isTerminationNode" has two params, but the code up there only has one. No wonder it goes wrong.

[huntergregal]

try .unsanitized{ it,s -> it._().isCheck }