diff --git a/eurostat_to_dbnomics.py b/eurostat_to_dbnomics.py
index a38cc631a98275f9c571d5e3a29577b90e527f84..06253eb225ff98f71fe42000df3c09ecdf7609c8 100755
--- a/eurostat_to_dbnomics.py
+++ b/eurostat_to_dbnomics.py
@@ -392,10 +392,10 @@ def main():
     dataset_index_file_path = os.path.abspath(os.path.join(args.target_dir, "objects", "info", "datasets"))
     if os.path.isfile(dataset_index_file_path):
         with open(dataset_index_file_path) as dataset_index_file:
-            dataset_tree_id_by_dataset_code = dict(map(
-                lambda line: line[:-1].split("\t"),  # Remove final "\n".
-                dataset_index_file.readlines(),
-            ))
+            def to_pair(line):
+                fragments = line[:-1].split("\t")  # Remove final "\n".
+                return fragments[0], fragments[1]
+            dataset_tree_id_by_dataset_code = dict(map(to_pair, dataset_index_file.readlines()))
 
     root_branch_element = toc_element.find("nt:branch", namespaces=toc_nsmap)
     toc_to_git_tree_and_packs(repo, dataset_tree_id_by_dataset_code,