@bellisk This code won't work because `self` is only available to functions inside the class `HarvesterBase`.
Better to do the check on the `_create_or_update_package` method directly:

```diff
index c2855e4..a691972 100644
--- a/ckanext/harvest/harvesters/base.py
+++ b/ckanext/harvest/harvesters/base.py
@@ -150,10 +150,11 @@ class HarvesterBase(SingletonPlugin):
                 'ignore_auth': True,
             }
 
-            tags = package_dict.get('tags', [])
-            tags = [munge_tag(t) for t in tags]
-            tags = list(set(tags))
-            package_dict['tags'] = tags
+            if self.config and self.config.get('clean_tags', False):
+                tags = package_dict.get('tags', [])
+                tags = [munge_tag(t) for t in tags]
+                tags = list(set(tags))
+                package_dict['tags'] = tags
 
             # Check if package exists
             data_dict = {}
```