diff --git a/app/scodoc/sco_import_etuds.py b/app/scodoc/sco_import_etuds.py
index 6d4988d1..da117b5d 100644
--- a/app/scodoc/sco_import_etuds.py
+++ b/app/scodoc/sco_import_etuds.py
@@ -154,9 +154,9 @@ def sco_import_generate_excel_sample(
     with_codesemestre=True,
     only_tables=None,
     with_groups=True,
-    exclude_cols=[],
-    extra_cols=[],
-    group_ids=[],
+    exclude_cols=(),
+    extra_cols=(),
+    group_ids=(),
 ):
     """Generates an excel document based on format fmt
     (format is the result of sco_import_format())
@@ -167,7 +167,7 @@ def sco_import_generate_excel_sample(
     style = sco_excel.excel_make_style(bold=True)
     style_required = sco_excel.excel_make_style(bold=True, color=COLORS.RED)
     titles = []
-    titlesStyles = []
+    titles_styles = []
     for l in fmt:
         name = l[0].lower()
         if (not with_codesemestre) and name == "codesemestre":
@@ -177,15 +177,15 @@ def sco_import_generate_excel_sample(
         if name in exclude_cols:
             continue  # colonne exclue
         if int(l[3]):
-            titlesStyles.append(style)
+            titles_styles.append(style)
         else:
-            titlesStyles.append(style_required)
+            titles_styles.append(style_required)
         titles.append(name)
     if with_groups and "groupes" not in titles:
         titles.append("groupes")
-        titlesStyles.append(style)
+        titles_styles.append(style)
     titles += extra_cols
-    titlesStyles += [style] * len(extra_cols)
+    titles_styles += [style] * len(extra_cols)
     if group_ids:
         groups_infos = sco_groups_view.DisplayedGroupsInfos(group_ids)
         members = groups_infos.members
@@ -194,7 +194,7 @@ def sco_import_generate_excel_sample(
             % (group_ids, len(members))
         )
         titles = ["etudid"] + titles
-        titlesStyles = [style] + titlesStyles
+        titles_styles = [style] + titles_styles
         # rempli table avec données actuelles
         lines = []
         for i in members:
@@ -213,7 +213,7 @@ def sco_import_generate_excel_sample(
     else:
         lines = [[]]  # empty content, titles only
     return sco_excel.excel_simple_table(
-        titles=titles, titles_styles=titlesStyles, sheet_name="Etudiants", lines=lines
+        titles=titles, titles_styles=titles_styles, sheet_name="Etudiants", lines=lines
     )
 
 
@@ -256,7 +256,7 @@ def scolars_import_excel_file(
     formsemestre_id=None,
     check_homonyms=True,
     require_ine=False,
-    exclude_cols=[],
+    exclude_cols=(),
 ):
     """Importe etudiants depuis fichier Excel
     et les inscrit dans le semestre indiqué (et à TOUS ses modules)
@@ -302,7 +302,8 @@ def scolars_import_excel_file(
             else:
                 unknown.append(f)
         raise ScoValueError(
-            "Nombre de colonnes incorrect (devrait être %d, et non %d) <br/> (colonnes manquantes: %s, colonnes invalides: %s)"
+            """Nombre de colonnes incorrect (devrait être %d, et non %d)<br/>
+            (colonnes manquantes: %s, colonnes invalides: %s)"""
             % (len(titles), len(fs), list(missing.keys()), unknown)
         )
     titleslist = []
@@ -313,7 +314,7 @@ def scolars_import_excel_file(
     # ok, same titles
     # Start inserting data, abort whole transaction in case of error
     created_etudids = []
-    NbImportedHomonyms = 0
+    np_imported_homonyms = 0
     GroupIdInferers = {}
     try:  # --- begin DB transaction
         linenum = 0
@@ -377,10 +378,10 @@ def scolars_import_excel_file(
                     if val:
                         try:
                             val = sco_excel.xldate_as_datetime(val)
-                        except ValueError:
+                        except ValueError as exc:
                             raise ScoValueError(
                                 f"date invalide ({val}) sur ligne {linenum}, colonne {titleslist[i]}"
-                            )
+                            ) from exc
                 # INE
                 if (
                     titleslist[i].lower() == "code_ine"
@@ -404,15 +405,17 @@ def scolars_import_excel_file(
                 if values["code_ine"] and not is_new_ine:
                     raise ScoValueError("Code INE dupliqué (%s)" % values["code_ine"])
                 # Check nom/prenom
-                ok, NbHomonyms = sco_etud.check_nom_prenom(
-                    cnx, nom=values["nom"], prenom=values["prenom"]
-                )
+                ok = False
+                if "nom" in values and "prenom" in values:
+                    ok, nb_homonyms = sco_etud.check_nom_prenom(
+                        cnx, nom=values["nom"], prenom=values["prenom"]
+                    )
                 if not ok:
                     raise ScoValueError(
                         "nom ou prénom invalide sur la ligne %d" % (linenum)
                     )
-                if NbHomonyms:
-                    NbImportedHomonyms += 1
+                if nb_homonyms:
+                    np_imported_homonyms += 1
                 # Insert in DB tables
                 formsemestre_id_etud = _import_one_student(
                     cnx,
@@ -425,11 +428,11 @@ def scolars_import_excel_file(
                 )
 
         # Verification proportion d'homonymes: si > 10%, abandonne
-        log("scolars_import_excel_file: detected %d homonyms" % NbImportedHomonyms)
-        if check_homonyms and NbImportedHomonyms > len(created_etudids) / 10:
+        log("scolars_import_excel_file: detected %d homonyms" % np_imported_homonyms)
+        if check_homonyms and np_imported_homonyms > len(created_etudids) / 10:
             log("scolars_import_excel_file: too many homonyms")
             raise ScoValueError(
-                "Il y a trop d'homonymes (%d étudiants)" % NbImportedHomonyms
+                "Il y a trop d'homonymes (%d étudiants)" % np_imported_homonyms
             )
     except:
         cnx.rollback()