Update mslib/mscolab/models.py

Co-authored-by: Matthias Riße <[email protected]>

Author: ReimarBauer

mslib/mscolab/models.py

@@ -216,5 +216,7 @@ def __init__(self, op_id, u_id, commit_hash, version_name=None, comment=None):
         self.op_id = int(op_id)
         self.u_id = int(u_id)
         self.commit_hash = str(commit_hash)
-        self.version_name = version_name
-        self.comment = comment
+        if version_name is not None:
+            self.version_name = str(version_name)
+        if comment is not None:
+            self.comment = str(comment)