minor changes

src/vt/mean_trsfs.py

@@ -64,7 +64,8 @@ def mean_trsfs(trsfs, params="", **kwargs):
                 print(str(proc) + ": unexpected type '" + str(type(kwargs["out_file_path"]))
                       + "'for 'kwargs[\"out_file_path\"]'")
             return None
-        return subprocess.call(["meanTrsfs", "-trsfs"] + trsfs + ["-res", kwargs["out_file_path"]] + params.split())
+        cmd_params = ["-trsfs"] + trsfs + ["-res", kwargs["out_file_path"]]
+        return subprocess.run(["meanTrsfs"] + cmd_params + params.split()).returncode
 
     #
     # python procedure