I am trying to generate a claim for a jwt using oathkeeper. It works for single fields from the AuthenticationSession but not for multiple ones. anyone more experienced in go templates have any suggestions of another technique? I am trying: {"user": "{{ printf "%s.%s" .Extra.identity.traits.first .Extra.identity.traits.last }}" and the trait is embedded as "user": "%!s(<nil>).%!s(<nil>)" but if I use a single variable it works, e.g.: "email": "{{ .Extra.identity.traits.email }}"