Analysis of feature FK_STENOK in relation to chronic heart failure:

Based on prior knowledge, the functional class of angina pectoris (FK_STENOK) provides information about the severity of symptoms experienced by the patient. Chronic heart failure is often associated with the progression of cardiovascular disease and can lead to changes in the functional class of angina.

To determine if FK_STENOK is related to chronic heart failure, we can analyze the distribution of FK_STENOK values in patients with and without chronic heart failure.

Here is a dictionary showing the possible FK_STENOK values for each target class:

```json
{
	"no": ["there is no angina pectoris", "II FC", "IV FC"],  
	"yes": ["II FC", "IV FC", "I FC", "III FC."]
}
```

Explanation:
- For patients with no chronic heart failure (target class "no"), the possible FK_STENOK values observed are: "there is no angina pectoris", "II FC", and "IV FC".
- For patients with chronic heart failure (target class "yes"), the possible FK_STENOK values observed are: "II FC", "IV FC", "I FC", and "III FC."

Note: The values "I FC" and "III FC" are only observed in patients with chronic heart failure (target class "yes"). The value "there is no angina pectoris" is only observed in patients without chronic heart failure (target class "no").