Fix set formatter

Author: jenshnielsen

src/qcodes/parameters/parameter.py

@@ -56,8 +56,8 @@ def set_parameter_write(self: Parameter, *args) -> None:
             assert isinstance(cmd, str)
             # TODO it is possible to format str with additional args.
             # this does not seem to have been tested
-            cmd.format(*args)
-            return function(cmd)
+            formatted_cmd = cmd.format(*args)
+            return function(formatted_cmd)
 
         return set_parameter_write