panic: template: package.html:33: function "example_html" not defined

runtime.panic+0xac /home/finn/workspace/go/src/pkg/runtime/proc.c:1254
        runtime.panic(0x5f6e00, 0xf840057360)
template.Must+0x4e /home/finn/workspace/go/src/pkg/template/helper.go:24
        template.Must(0x0, 0xf84001b570, 0xf840057360, 0x0, 0xf84001b570, ...)
main.readTemplate+0x30c /home/finn/workspace/go/src/cmd/godoc/godoc.go:543
        main.readTemplate(0x66a90c, 0x6b6361700000000c, 0xf8400336f0, 0x4131b6, 0x5f3968, ...)
main.readTemplates+0xd6 /home/finn/workspace/go/src/cmd/godoc/godoc.go:565
        main.readTemplates()
main.main+0x1b7 /home/finn/workspace/go/src/cmd/godoc/main.go:254
        main.main()
runtime.mainstart+0xf /home/finn/workspace/go/src/pkg/runtime/amd64/asm.s:78
        runtime.mainstart()
runtime.goexit /home/finn/workspace/go/src/pkg/runtime/proc.c:246
        runtime.goexit()
----- goroutine created by -----
_rt0_amd64+0xc9 /home/finn/workspace/go/src/pkg/runtime/amd64/asm.s:65