handle error: storage belongs to different cluster

Author: BalabaDmitri

src/cluster.py

@@ -650,8 +650,13 @@ def update_synchronous_node_count(self, units: int = None) -> None:
 
 
     def cluster_system_id_mismatch(self, unit_name: str) -> bool:
-        """Check if the Patroni service is down and
-        if there is the error storage belongs to foreign cluster in its logs."""
+        """Check if the Patroni service is down.
+
+        If there is the error storage belongs to third-party cluster in its logs.
+
+        Returns:
+            "True" if an error occurred due to the fact that the storage belongs to someone else's cluster.
+        """
         last_log_file = self._last_patroni_log_file()
         unit_name = unit_name.replace("/", "-")
         if f" CRITICAL: system ID mismatch, node {unit_name} belongs to a different cluster:" in last_log_file: