diff --git a/CHANGELOG.md b/CHANGELOG.md
index 087316d2c4f56f2ab73fbcf7316d24be65d0393b..0fea84a3f8f8c1f4ef11753758147c6be2457988 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -15,6 +15,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Creation of CrawlerRun Records that contain status information about data
   integration of the crawler if the `pycaosdb.ini` contains a `[caoscrawler]`
   with `create_crawler_status_records=True`.
+- The Crawler `synchronize` function now takes list of RecordType names. 
+  Records that have the given names as parents are excluded from inserts or
+  updates
 
 ### Changed ###
 
diff --git a/src/caoscrawler/crawl.py b/src/caoscrawler/crawl.py
index ca8c41c05ada4b05966e500b4d1d61ad8ef1e582..4f2b7b670849029f2cbfdeadcf1c87d5f3c5bb90 100644
--- a/src/caoscrawler/crawl.py
+++ b/src/caoscrawler/crawl.py
@@ -823,8 +823,8 @@ class Crawler(object):
                     commit_changes: bool = True,
                     unique_names: bool = True,
                     crawled_data: Optional[list[db.Record]] = None,
-                    no_insert_RTs=Optional[list[str]],
-                    no_update_RTs=Optional[list[str]],
+                    no_insert_RTs: Optional[list[str]] = None,
+                    no_update_RTs: Optional[list[str]] = None,
                     ):
         """
         This function applies several stages: