new: dev: provided new ``image_exposed_ports_0`` function for charms.

bin/compose

@@ -289,7 +289,11 @@ cached_cmd_on_base_image() {
 }
 export -f cached_cmd_on_base_image
 
-
+image_exposed_ports_0() {
+    local image="$1"
+    docker inspect --format='{{range $p, $conf := .Config.ExposedPorts}}{{$p}}{{"\x00"}}{{end}}' "$image"
+}
+export -f image_exposed_ports_0
 
 ##
 ## Generic