How to resolve error "Microfllow does not return an object"

My app allows creation of a list of entities. The list of entities are displayed on an ‘overview’ page. I want to display on the same overview page, the count of the number of entities. I am trying to do this via a microflow that currently has only two activities  a) Creates the list of entities b) Obtains the count of the entities This throws the error ‘Microflow xxx does not return an object’. Can’t yet find a way to resolve this. Any advice/suggestions would be appreciated. Thank you