handling different versions of Postgres of unit

Author: BalabaDmitri

src/charm.py

@@ -1585,7 +1585,7 @@ def client_relations(self) -> List[Relation]:
         return relations
 
     def _validate_database_version(self, version: str) -> bool:
-        """Checking that only one version of Postgres is used"""
+        """Checking that only one version of Postgres is used."""
         peer_db_version = self.app_peer_data.get("database-version")
 
         if self.unit.is_leader() and peer_db_version is None: