Resolve "Cancel Invoices"

Closes #56 (closed)

l10n_mx_facturae/models/account_invoice.py

         """Verify cancellation status"""
         # TODO: Is this really needed? Maybe we can reuse the action_cancel
         for account_invoice in self:
-            status_cancelacion = account_invoice.consult_cfdi_cancellation_status()
-            if status_cancelacion is None:
-                continue
-            elif status_cancelacion is False:
-                self.undo_waiting_state()
-            else:
-                try:
-                    account_invoice.action_cancel()
-                except Exception as e:
-                    _logger.info(e)
-                    continue
+            try:
+                with self.env.cr.savepoint():
+                    status_cancelacion = \
+                        account_invoice.consult_cfdi_cancellation_status()
+                    if status_cancelacion is None:
+                        continue
+                    elif status_cancelacion is False:
+                        self.undo_waiting_state()
+                    else:
+                        try:
+                            account_invoice.action_cancel()
+                        except Exception as e:
+                            _logger.info(e)
+                            account_invoice.message_post(
+                                "The invoice could not cancelad"
+                            )
+                            continue
+            except Exception as e:
+                account_invoice.message_post(
+                    "The invoice %s could not be cancelad "
+                    "due to the following error %s."
+                    % (account_invoice.name, e)
+                )
 
     @api.multi
     def _validate_cfdi_data(self):