package errhttp type BadGateway interface { ServerError BadGateway() } type internalBadGateway struct { err error } func BadGatewayWrap(err error) error { return internalBadGateway{ err:err, } } func (receiver internalBadGateway) Error() string { return receiver.err.Error() } func (receiver internalBadGateway) Err() error { return receiver.err } func (internalBadGateway) ServerError() { // Nothing here. } func (internalBadGateway) BadGateway() { // Nothing here. }