package errhttp type NotImplemented interface { ServerError NotImplemented() } var _ NotImplemented = internalNotImplemented{} type internalNotImplemented struct { err error } func NotImplementedWrap(err error) error { return internalNotImplemented{ err:err, } } func (receiver internalNotImplemented) Error() string { return receiver.err.Error() } func (receiver internalNotImplemented) Err() error { return receiver.err } func (internalNotImplemented) ServerError() { // Nothing here. } func (internalNotImplemented) NotImplemented() { // Nothing here. } func (receiver internalNotImplemented) Unwrap() error { return receiver.err }