Gist to make and return an error that you can use to represent a go function that is not yet implemented based on where the function is called from.

notImplemented.go

package dev

import (
	"fmt"
	"log"
	"runtime"
	"strings"
)

func notImplemented() error {
	pc := make([]uintptr, 10) // at least 1 entry needed
	runtime.Callers(2, pc)
	f := runtime.FuncForPC(pc[0])
	file, line := f.FileLine(pc[0])
	index := strings.LastIndex(file, "/") + 1
	if len(file) >= index {
		file = file[index:]
	}
	funcName := f.Name()
	funcName = funcName[strings.Index(funcName, ".")+1:]
	err := fmt.Errorf("Implement: %v:%v @%v\n", file, line, funcName)
	log.Println(err.Error())
	return err
}

Just add this function and call it you get an error something like this:

Implement: utils.go:249 @verifyName

Where utils.go is the file and verifyName is the name of the function that is not yet implemented.