diff --git a/ihatemoney/forms.py b/ihatemoney/forms.py
index 48c39c87..fe966778 100644
--- a/ihatemoney/forms.py
+++ b/ihatemoney/forms.py
@@ -323,14 +323,14 @@ class BillForm(FlaskForm):
 
     def export(self, project):
         return Bill(
-            float(self.amount.data),
-            self.date.data,
-            self.external_link.data,
-            str(self.original_currency.data),
-            Person.query.get_by_ids(self.payed_for.data, project),
-            self.payer.data,
-            project.default_currency,
-            self.what.data,
+            amount=float(self.amount.data),
+            date=self.date.data,
+            external_link=self.external_link.data,
+            original_currency=str(self.original_currency.data),
+            owers=Person.query.get_by_ids(self.payed_for.data, project),
+            payer_id=self.payer.data,
+            project_default_currency=project.default_currency,
+            what=self.what.data,
         )
 
     def save(self, bill, project):
diff --git a/ihatemoney/models.py b/ihatemoney/models.py
index 50f919b4..7877b410 100644
--- a/ihatemoney/models.py
+++ b/ihatemoney/models.py
@@ -325,27 +325,27 @@ class Project(db.Model):
     def import_bills(self, bills: list):
         """Import bills from a list of dictionaries"""
         # Add members not already in the project
-        members_project = [str(m) for m in self.members]
-        members_new = [
-            m for m in get_members(bills) if str(m[0]) not in members_project
+        project_members = [str(m) for m in self.members]
+        new_members = [
+            m for m in get_members(bills) if str(m[0]) not in project_members
         ]
-        for m in members_new:
+        for m in new_members:
             Person(name=m[0], project=self, weight=m[1])
         db.session.commit()
 
         # Import bills not already in the project
-        bills_project = self.get_pretty_bills()
+        project_bills = self.get_pretty_bills()
         id_dict = {m.name: m.id for m in self.members}
         for b in bills:
             same = False
-            for b_p in bills_project:
-                if same_bill(b_p, b):
+            for p_b in project_bills:
+                if same_bill(p_b, b):
                     same = True
                     break
             if not same:
                 # Create bills
-                db.session.add(
-                    Bill(
+                try:
+                    new_bill = Bill(
                         amount=b["amount"],
                         date=parse(b["date"]),
                         external_link="",
@@ -355,7 +355,9 @@ class Project(db.Model):
                         project_default_currency=self.default_currency,
                         what=b["what"],
                     )
-                )
+                except Exception as e:
+                    raise ValueError(f"Unable to import csv data: {repr(e)}")
+                db.session.add(new_bill)
         db.session.commit()
 
     def remove_member(self, member_id):
diff --git a/ihatemoney/utils.py b/ihatemoney/utils.py
index 19d3aea6..96b80816 100644
--- a/ihatemoney/utils.py
+++ b/ihatemoney/utils.py
@@ -158,7 +158,12 @@ def csv2list_of_dicts(csv_to_convert):
     reader = csv.DictReader(csv_file)
     result = []
     for r in reader:
-        # cospend filtering
+        """
+        cospend embeds various data helping (cospend) imports
+        'deleteMeIfYouWant' lines contains users
+        'categoryname' table contains categories description
+        we don't need them as we determine users and categories from bills
+        """
         if r["what"] == "deleteMeIfYouWant":
             continue
         elif r["what"] == "categoryname":