diff --git a/qurator/modstool/lib.py b/qurator/modstool/lib.py
index c22689e..b24b698 100644
--- a/qurator/modstool/lib.py
+++ b/qurator/modstool/lib.py
@@ -162,6 +162,7 @@ class TagGroup:
         return self
 
     def merge_sub_tags_to_set(self):
+        from .modstool import mods_to_dict
         value = {}
 
         sub_dicts = [mods_to_dict(e) for e in self.group]
diff --git a/qurator/modstool/modstool.py b/qurator/modstool/modstool.py
index bc7429b..a6fe164 100755
--- a/qurator/modstool/modstool.py
+++ b/qurator/modstool/modstool.py
@@ -14,7 +14,7 @@ import click
 import pandas as pd
 from tqdm import tqdm
 
-from .lib import sorted_groupby, TagGroup, ns
+from .lib import sorted_groupby, TagGroup, ns, flatten
 
 
 
diff --git a/qurator/modstool/tests/test_mets.py b/qurator/modstool/tests/test_mets.py
index 76aa73f..315c7b6 100644
--- a/qurator/modstool/tests/test_mets.py
+++ b/qurator/modstool/tests/test_mets.py
@@ -1,7 +1,8 @@
 import xml.etree.ElementTree as ET
 
 
-from .. import mets_to_dict, flatten
+from qurator.modstool.modstool import mets_to_dict
+from qurator.modstool.lib import flatten
 
 
 def dict_fromstring(x):
diff --git a/qurator/modstool/tests/test_modstool.py b/qurator/modstool/tests/test_modstool.py
index b13586a..c31e3e8 100644
--- a/qurator/modstool/tests/test_modstool.py
+++ b/qurator/modstool/tests/test_modstool.py
@@ -1,8 +1,10 @@
+from tkinter import W
 import pytest
 import xml.etree.ElementTree as ET
 
 
-from .. import mods_to_dict, flatten
+from qurator.modstool.modstool import mods_to_dict
+from qurator.modstool.lib import flatten
 
 
 def dict_fromstring(x):