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

Based on my prior knowledge, the feature n_p_ecg_p_12, which represents the presence of Complete RBBB on ECG at the time of admission to the hospital, might show a positive relationship with chronic heart failure. It is possible for patients with chronic heart failure to have Complete RBBB on ECG. Thus, both "no" and "yes" values of the n_p_ecg_p_12 feature can be present in the patients who show chronic heart failure. However, it is also common for patients without chronic heart failure to have Complete RBBB on ECG. Thus, the n_p_ecg_p_12 feature can also have a "no" value for patients without chronic heart failure.