Fix typo

bigbluebutton/api/bigbluebutton.py

@@ -218,7 +218,7 @@ class BigBlueButton:
                  and return code)
         """
         if self.host is None:
-            raise ValueError("Server {self.name} has no hostname set")
+            raise ValueError(f"Server {self.name} has no hostname set")
         args: List[str] = ["ssh", self.host] + list(command)
 
         logger.info(f"Running SSH command {args} on {self.name}")