no check if no modified_fields

account.py

@@ -197,6 +197,17 @@ class MoveLine(metaclass=PoolMeta):
                     'hierarchies.'),
                 })
 
+
+    @classmethod
+    def check_modify(cls, lines, modified_fields=None):
+        '''
+        Check if the lines can be modified
+        '''
+        if modified_fields is None:
+            return
+
+        super(MoveLine, cls).check_modify(lines, modified_fields)
+
     @classmethod
     def validate(cls, lines):
         super(MoveLine, cls).validate(lines)