```json
{
	"no": ["no"], 
	"yes": ["yes"]
}
```
Based on the feature description and the task, we can infer that the presence of obesity in the patient's medical history (endocr_02 = "yes") may be a contributing factor to chronic heart failure. In this case, the feature "endocr_02" directly indicates whether or not the patient has a history of obesity.

The dictionary shows that the possible values for the "endocr_02" feature are "no" and "yes". For the target class "no" (no chronic heart failure), the only possible value for "endocr_02" is "no". For the target class "yes" (chronic heart failure), the only possible value for "endocr_02" is "yes".