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

In this case, the feature "zab_leg_06" represents whether the patient has a history of pulmonary tuberculosis. 
The dictionary shows that for the target class "no" (indicating no chronic heart failure), the only possible value for "zab_leg_06" is "no". 
For the target class "yes" (indicating the presence of chronic heart failure), the only possible value for "zab_leg_06" is "yes".