Based on prior knowledge, I understand that thyrotoxicosis is a condition caused by an overactive thyroid gland, characterized by high levels of thyroid hormones in the body. Chronic heart failure, on the other hand, refers to a condition where the heart is unable to pump blood efficiently to meet the body's needs.

Analyzing the relationship between the feature "endocr_03" (Thyrotoxicosis in the anamnesis) and the task of determining if the patient has chronic heart failure, we can make some assumptions:

1. Thyrotoxicosis itself does not directly indicate chronic heart failure. Thyrotoxicosis can cause various cardiovascular effects, but it does not necessarily mean the patient has chronic heart failure.

2. However, in some cases, long-standing untreated or severe thyrotoxicosis can lead to heart muscle damage, which can potentially result in chronic heart failure.

With these assumptions in mind, we can create a dictionary to present the possible values of the feature "endocr_03" for each target class:

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

In this case, the "endocr_03" feature has two possible values: "no" and "yes". For the target class "no" (indicating no chronic heart failure), the only possible value of "endocr_03" is "no". For the target class "yes" (indicating chronic heart failure), the only possible value of "endocr_03" is "yes".