```json
{
	"no": ["no"], 
	"yes": ["yes"]
}
```
Based on the feature "zab_leg_06" indicating the presence or absence of pulmonary tuberculosis in the patient's medical history, the possible values for this feature are "no" and "yes". 

For the task of determining whether the patient shows chronic heart failure, the analysis of this feature suggests that the presence or absence of pulmonary tuberculosis (as indicated by the feature "zab_leg_06") does not directly correlate with chronic heart failure. Hence, the values for the feature are independent of the target variable, and there is no specific relationship between "zab_leg_06" and chronic heart failure.