code: func (e *Error) Equal(err error) bool {
  	originErr := errors.Cause(err)
  	if originErr == nil {
  		return false
  	}
  	inErr, ok := originErr.(*Error)
  	return ok && e.class == inErr.class && e.code == inErr.code
  }
docs: // Equal checks if err is equal to e.