diff --git a/.github/workflows/checks.yml b/.github/workflows/checks.yml
index 5cd194e..1775aaf 100644
--- a/.github/workflows/checks.yml
+++ b/.github/workflows/checks.yml
@@ -1,6 +1,7 @@
+env:
+  PYTHONDEVMODE: 1
 on:
   workflow_call:
-
 jobs:
   run-checks:
     runs-on: ubuntu-latest
diff --git a/docling_ibm_models/reading_order/reading_order_rb.py b/docling_ibm_models/reading_order/reading_order_rb.py
index 22918a1..f1a740b 100644
--- a/docling_ibm_models/reading_order/reading_order_rb.py
+++ b/docling_ibm_models/reading_order/reading_order_rb.py
@@ -201,8 +201,8 @@ def predict_merges(
                     )
                 ):
 
-                    m1 = re.fullmatch(".+([a-z\,\-])(\s*)", elem.text)
-                    m2 = re.fullmatch("(\s*[a-z])(.+)", sorted_elements[ind_p1].text)
+                    m1 = re.fullmatch(r".+([a-z\,\-])(\s*)", elem.text)
+                    m2 = re.fullmatch(r"(\s*[a-z])(.+)", sorted_elements[ind_p1].text)
 
                     if m1 and m2:
                         merges[elem.cid] = [sorted_elements[ind_p1].cid]