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

Based on the given feature description and task, it seems that the presence of chronic pneumonia in the anamnesis (zab_leg_04) is an indicator for chronic heart failure. If the patient has chronic pneumonia in their medical history, then it is likely that they will have chronic heart failure. Therefore, the possible values of the feature zab_leg_04 for the target class "no" would be "no" and for the target class "yes" would be "yes".