L2SS-758: Fix typo

docker-compose/tango-prometheus-exporter/code/tango-prometheus-client.py

@@ -97,7 +97,7 @@ class CustomCollector(object):
             return None
 
         # (labels, value)
-        return ([dev.dev_name(), attr_info.name, str_value, data_type, f"{x:02}", f"{y:02}", f"{idx:03}"]], float_value)
+        return ([dev.dev_name(), attr_info.name, str_value, data_type, f"{x:02}", f"{y:02}", f"{idx:03}"], float_value)
 
     def metrics_scalar(self, dev, attr_info, attr_value):
         """ Return all metrics for a given SCALAR attribute. """