{{- $pubDate := .PublishDate -}}
{{- if $pubDate.IsZero -}}
    {{- $pubDate = .Site.Params.siteCreatedTime -}}
{{- end -}}
{{- $pubDate = dateFormat "2006-01-02T15:04:05-07:00" $pubDate -}}

{{- $modDate := .Lastmod -}}
{{- if $modDate.IsZero -}}
    {{- $modDate = .Site.Params.siteCreatedTime -}}
{{- end -}}
{{- $modDate = dateFormat "2006-01-02T15:04:05-07:00" $modDate -}}

{{- return dict "pubDate" $pubDate "modDate" $modDate -}}