how to get config file from the parent chart to dependency chart

I am using the following file structure

├───mainfests
│   └───[app_name]
│       ├───charts
│       │   └───base-0.0.1.tgz
│       ├───templates
│       ├───Chart.yaml
│       └───app_name.config
│
└───base
    └───[chart]
        └───templates
            └───configmap.yaml
        

where mainfests/[app_name]/Chart.yaml contains

dependencies:
- name: base
  version: 0.0.1
  repository: "file://./charts/base-0.0.1.tgz"

and base/[chart]/templates/configmap.yaml contains

apiVersion: v1
kind: ConfigMap
metadata:
  name: project-app_name
data:
  app_name.config: |-
{{ tpl (.Files.Get "app_name.config") . | indent 4 }}

how to get app_name.config correctly from the parent chart to dependency chart