Using an overlay within an overlay

config.yml

---
vlans:
- vlan-id: 10
- vlan-id: 20
- vlan-id: 30
some_other_configuration: #! some other config here

overlay.yml

#@ load("@ytt:overlay", "overlay")

#@ def with_name(vlan):
#@overlay/match missing_ok=True
vlan-name: #@ "vlan{}".format(vlan["vlan-id"])
#@ end

#@overlay/match by=overlay.all
---
vlans:
#@overlay/match by=lambda idx, left, right: "vlan-id" in left, expects="1+"
#@overlay/replace via=lambda left, right: overlay.apply(left, with_name(left))
-