Based on prior knowledge, we can analyze the relationship between the feature "STENOK_AN" and the task of predicting chronic heart failure.

From the feature description, it appears that "STENOK_AN" represents the presence or absence of exertional angina pectoris in the patient's medical history. Angina pectoris is chest pain or discomfort that occurs when the heart muscle does not receive enough blood. Therefore, it is possible that patients with a history of exertional angina pectoris may be more likely to develop chronic heart failure.

To create the dictionary, let's analyze the possible values of "STENOK_AN" for each target class.

For the target class "no" (indicating no chronic heart failure), it is reasonable to assume that patients who have never experienced exertional angina pectoris would be part of this class. Therefore, the possible values of "STENOK_AN" for target class "no" may include "never". However, since the feature description does not provide information about the relationship between other values of "STENOK_AN" and the absence of chronic heart failure, we cannot include other values in the dictionary.

For the target class "yes" (indicating chronic heart failure), we cannot determine a specific relationship between the other possible values of "STENOK_AN" and the presence of chronic heart failure. Since the feature description does not provide information about the importance of other values of "STENOK_AN" for this task, we cannot include those values in the dictionary. Therefore, for the target class "yes", we can only include the value "never" as a possible value of "STENOK_AN".

Based on this analysis, the dictionary will have the following format:

```json
{
	"no": ["never"],
	"yes": ["never"]
}
```

Please note that this analysis assumes a conservative approach, including only the values that we can confidently associate with each target class.