Merge pull request #37 from Seb-sti1/value-error

Fix #16

README.md

@@ -13,6 +13,7 @@ To convert rm files to other formats, you can use [rmc](https://github.com/rickl
 Fixes:
 
 - Fix AssertionError when some ids are missing in a `CrdtSequence` ([#36](https://github.com/ricklupton/rmscene/pull/36))
+- Fix ValueError when the node_id is missing in a `SceneGroupItemBlock` ([#16](https://github.com/ricklupton/rmscene/issues/16)) 
 - Store any unparsed data in blocks as raw bytes to allow for round-trip saving of files written in a newer format than the parsing code knows about.
 
 ### v0.6.0

src/rmscene/scene_stream.py

@@ -886,6 +886,8 @@ def build_tree(tree: SceneTree, blocks: Iterable[Block]):
         elif isinstance(b, SceneGroupItemBlock):
             # Add this entry to children of parent_id
             node_id = b.item.value
+            if node_id is None:
+                continue
             if node_id not in tree:
                 raise ValueError(
                     "Node does not exist for SceneGroupItemBlock: %s" % node_id