FileBone setSkelValue

[sveneberth]

diff --git a/importer.py b/importer.py
index 04f48c9..6995c52 100644
--- a/importer.py
+++ b/importer.py
@@ -376,10 +376,10 @@ class Importer(requests.Session):
                                 logger.error(f"Unable to set bone {boneName} to {key}")
 
                     else:
-                        assert entry["rel"]
+                        assert "rel" in entry, f"rel not in {entry=} ({boneName=}, {skel.skeletonCls.__name__=})"
                         usingSkel = bone.using()
                         usingSkel.unserialize(knownFiles[fileName]["rel"] if fileName in knownFiles else {})
-                        changes += self.translate(usingSkel, entry["rel"])
+                        changes += self.translate(usingSkel, entry["rel"] or {})
 
                         if key:
                             if skel.setBoneValue(boneName, (key, usingSkel), append=bone.multiple, language=lang):
-- 
2.49.0