```py
python rabbit.py

	if cred.ParentUser != "" {
		principalID = cred.ParentUser
	}

	// Success.
	m := map[string]string{
		"region":          region,
		"principalId":     principalID,
		"sourceIPAddress": handlers.GetSourceIP(r),
		// Add more fields here.
	}
	if rangeField := r.Header.Get(xhttp.Range); rangeField != "" {
		m["range"] = rangeField
	}