Fanna Lautenbach
--- a/ldvspec/lofardata/views.py
+++ b/ldvspec/lofardata/views.py
+
+def combine_dataproducts_on_key(data_products, combined_data_products):
    for data_product in data_products:
-        for key, value in data_product.items():
-            if combined_data_products_on_key.get(key) and value not in combined_data_products_on_key.get(key):
-                combined_data_products_on_key[key].append(value)
-            else:
-                combined_data_products_on_key[key] = [value]
+        combined_data_products = fill_unique_nested_dict(data_product, combined_data_products)
+    return combined_data_products
+

+def fill_unique_nested_dict(data_product, combined_data_products_on_key):
+    for key, value in data_product.items():
+        if isinstance(value, dict):
+            combined_data_products_on_key = fill_unique_nested_dict(value, combined_data_products_on_key)