Merge pull request #718 from Nebukadneza/fix_delete_nodes

Delete datachange_callbacks only on copy of dict to delete them from

Author: oroulet

opcua/server/address_space.py

@@ -330,7 +330,7 @@ def _delete_node(self, item, user):
 
     def _delete_node_callbacks(self, nodedata):
         if ua.AttributeIds.Value in nodedata.attributes:
-            for handle, callback in nodedata.attributes[ua.AttributeIds.Value].datachange_callbacks.items():
+            for handle, callback in list(nodedata.attributes[ua.AttributeIds.Value].datachange_callbacks.items()):
                 try:
                     callback(handle, None, ua.StatusCode(ua.StatusCodes.BadNodeIdUnknown))
                     self._aspace.delete_datachange_callback(handle)