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

cidr: #@ ip.parse_cidr("not-a-valid-cidr")

+++

ERR: 
- ip.parse_cidr: invalid CIDR address: not-a-valid-cidr
    in <toplevel>
      stdin:3 | cidr: #@ ip.parse_cidr("not-a-valid-cidr")