code: func HereSkipping(e error, skip int) Error {
  	switch m := e.(type) {
  	case nil:
  		return nil
  	case *merryErr:
  		// optimization: only capture the stack once, since its expensive
  		return m.WithStackSkipping(1 + skip)
  	default:
  		return WrapSkipping(e, 1+skip)
  	}
  }
docs: // HereSkipping returns an error with a new stacktrace, at the call site
  // of HereSkipping() - skip frames.