NXWriter: dont write config if not existing

nabu/io/writer.py

@@ -68,16 +68,15 @@ class NXProcessWriter(Writer):
             nx_process['date'] = datetime.now().replace(microsecond=0).isoformat()
             nx_process['sequence_index'] = np.int32(processing_index)
 
-            if config is None:
-                config = {}
-            export_dict_to_h5(
-                config,
-                self.fname,
-                '/'.join([nx_process.name, 'configuration']),
-                overwrite_data=True,
-                mode="a"
-            )
-            nx_process['configuration'].attrs['NX_class'] = "NXcollection"
+            if config is not None:
+                export_dict_to_h5(
+                    config,
+                    self.fname,
+                    '/'.join([nx_process.name, 'configuration']),
+                    overwrite_data=True,
+                    mode="a"
+                )
+                nx_process['configuration'].attrs['NX_class'] = "NXcollection"
             nx_data = nx_process.require_group('results')
             nx_data.attrs['NX_class'] = "NXdata"
             nx_data.attrs['signal'] = "data"