{- if not .PublishDate.IsZero }}<meta property="article:published_time" {{ .PublishDate.Format $iso8601 | printf "content=%q" | safeHTMLAttr }} />
{{ else if not .Date.IsZero }}<meta property="article:published_time" {{ .Date.Format $iso8601 | printf "content=%q" | safeHTMLAttr }} />
{{ end }}
{{- if not .Lastmod.IsZero }}<meta property="article:modified_time" {{ .Lastmod.Format $iso8601 | printf "content=%q" | safeHTMLAttr }} />{{ end }}
{{- else }}
{{- if not .Date.IsZero }}<meta property="og:updated_time