package dpi import ( "errors" "fmt" ) var ( ErrInvalid = errors.New("invalid") ) type DecodeError struct { Reason string Err error } func (err DecodeError) Error() string { if err.Reason != "" { return fmt.Sprintf("dpi: %s: %v", err.Reason, err.Err.Error()) } return err.Error() } func (err DecodeError) Unwrap() error { return err.Err }