code: func SetFuncMapToEngine(funcMap map[string]interface{}, e Engine) *Mux {
  	return DefaultMux.SetFuncMapToEngine(funcMap, e)
  }
docs: // SetFuncMapToEngine sets or overrides a specific func map to a specific template engine
  // SharedFuncs stays untouched here.
  //
  // Call UseFuncMap if you want to set SharedFuncs and be applied
  // to all registered and future template engines registrations.