func pathNotFoundError(ctx context.Context, pathType, fullPath, requestedVersion string) error {
	if isActiveFrontendFetch(ctx) {
		return pathNotFoundErrorNew(fullPath, requestedVersion)
	}
	return &serverError{
		status: http.StatusNotFound,
		epage: &errorPage{
			messageTemplate: template.MakeTrustedTemplate(`<h3 class="Error-message">404 Not Found</h3>
				 <p class="Error-message">
				   If you think this is a valid {{.}} path, you can try fetching it following
				   the <a href="/about#adding-a-package">instructions here</a>.
				</p>`),
			MessageData: pathType,
		},
	}
}
// pathNotFoundError returns an error page with instructions on how to
// add a package or module to the site. pathType is always either the string
// "package" or "module".
pathNotFoundError returns an error page with instructions on how to
add a package or module to the site. pathType is always either the string
"package" or "module".
// pathNotFoundError returns an error page with instructions on how to // add a package or module to the site . pathType is always either the string // " package " or " module " .
func pathNotFoundError(ctx context.Context, pathType, fullPath, requestedVersion string) error {
	if isActiveFrontendFetch(ctx) {
		return pathNotFoundErrorNew(fullPath, requestedVersion)
	}
	return &serverError{
		status: http.StatusNotFound,
		epage: &errorPage{
			messageTemplate: template.MakeTrustedTemplate(`<h3 class="Error-message">404 Not Found</h3>
				 <p class="Error-message">
				   If you think this is a valid {{.}} path, you can try fetching it following
				   the <a href="/about#adding-a-package">instructions here</a>.
				</p>`),
			MessageData: pathType,
		},
	}
}
func pathNotFoundError ( ctx context . Context , pathType , fullPath , requestedVersion string ) error { if isActiveFrontendFetch ( ctx ) { return pathNotFoundErrorNew ( fullPath , requestedVersion ) } return & serverError { status : http . StatusNotFound , epage : & errorPage { messageTemplate : template . MakeTrustedTemplate ( `<h3 class="Error-message">404 Not Found</h3>
				 <p class="Error-message">
				   If you think this is a valid {{.}} path, you can try fetching it following
				   the <a href="/about#adding-a-package">instructions here</a>.
				</p>` ) , MessageData : pathType , } , } }
pathNotFoundError returns an error page with instructions on how to
add a package or module to the site.
pathNotFoundError returns an error page with instructions on how to add a package or module to the site .