diff --git a/l10n_it_withholding_tax/models/account.py b/l10n_it_withholding_tax/models/account.py
index 1b19046529c8..fabf84e38c92 100644
--- a/l10n_it_withholding_tax/models/account.py
+++ b/l10n_it_withholding_tax/models/account.py
@@ -97,7 +97,7 @@ def generate_wt_moves(self):
             payment_lines = wt_st.withholding_tax_id.payment_term.compute(
                 amount_wt,
                 rec_line_statement.date or False)
-            if payment_lines:
+            if payment_lines[0]:
                 p_date_maturity = payment_lines[0][0][0]
             wt_move_vals = {
                 'statement_id': wt_st.id,