diff --git a/invoice.py b/invoice.py
index 5661d4f..547d7dd 100644
--- a/invoice.py
+++ b/invoice.py
@@ -87,6 +87,8 @@ class Invoice(metaclass=PoolMeta):
         pool = Pool()
         SIILines = pool.get('aeat.sii.report.lines')
 
+        assert clause[1] in ('=', 'in')
+
         table = SIILines.__table__()
 
         cursor = Transaction().connection.cursor()
@@ -99,25 +101,32 @@ class Invoice(metaclass=PoolMeta):
             invoices.append(invoice)
             lines.append(id_)
 
+        values = clause[-1]
         is_none = False
-        c = clause[-1]
-        if isinstance(clause[-1], list):
+        if isinstance(clause[-1], (list, tuple, set)):
             if None in clause[-1]:
                 is_none = True
-                c.remove(None)
+                values.remove(None)
+        else:
+            is_none = bool(clause[-1] is None)
 
         c0 = []
-        if clause[-1] is None or is_none:
-            c0 = [('id', 'not in', invoices)]
+        if is_none:
+            c0 = [('sii_records', '=', None)]
 
-        clause2 = [tuple(('state',)) + tuple(clause[1:]),
-            ('id', 'in', lines)]
+        clause2 = [
+            ('state', ) + tuple(clause[1:2]) + (values, ),
+            ('id', 'in', lines)
+        ]
 
         res_lines = SIILines.search(clause2)
 
         if is_none:
-            return ['OR', c0, [
-                    ('id', 'in', [x.invoice.id for x in res_lines])]]
+            return [
+                'OR',
+                c0,
+                [('id', 'in', [x.invoice.id for x in res_lines])]
+            ]
         else:
             return [('id', 'in', [x.invoice.id for x in res_lines])]