```json
{
    "no": ["no"],
    "yes": ["yes"]
}
```

In this case, the feature `ritm_ecg_p_07` has two possible categories: "no" and "yes". For the target class "no" (patients without chronic heart failure), the possible value for `ritm_ecg_p_07` is "no". For the target class "yes" (patients with chronic heart failure), the possible value for `ritm_ecg_p_07` is "yes".