Referencing notebook exit value as a variable in a data pipeline

For my own implementation the delimited string just wasnt flexible enough - so here's a version using a JSON object as the notebook return value: 

Notebook pyspark:

lResult={"numUpdated":10,"message":"success","fruit":["apple","orange","grapes"]}
mssparkutils.notebook.exit(str(lResult))

Expression for varMessageStr:

Anonymous(activity('Test Notebook').output.result.exitValue).message

Expression for varNumUpdatedInt:

INT(json(activity('Test Notebook').output.result.exitValue).numUpdated)

Expression for varFruitArray:

Anonymous(activity('Test Notebook').output.result.exitValue).fruit