I have followed the Helm Subchart documentation to create a parent chart with a sub-chart.
When I install the parent chart, the sub-chart comes along for the ride. Great! However, if I try to install another instance of the parent chart with a different name, I get an error saying the sub-chart already exists.

Error: rendered manifests contain a resource that already exists. Unable to continue with install: existing resource conflict: kind: Service, namespace: my-namespace, name: my-subcharts-service

I had expected the sub-chart to be installed if it did not already exist. And if it did exist I expected everything to be ok. Eg I thought it would work like a package management system eg pip/yum/npm

Is there a way to share a sub chart (or other helm construct) between multiple instances of a parent chart?