From 27cf0f45df1a5ed524e7f72a9c00b7e9f0c7b10a Mon Sep 17 00:00:00 2001
From: Jochem Smit <jhsmit@gmail.com>
Date: Tue, 6 Jun 2023 20:03:03 +0200
Subject: [PATCH] metadata optional

---
 hdxms_datasets/datasets.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hdxms_datasets/datasets.py b/hdxms_datasets/datasets.py
index 85be60c..cf72f65 100644
--- a/hdxms_datasets/datasets.py
+++ b/hdxms_datasets/datasets.py
@@ -51,7 +51,7 @@ class HDXDataSet(object):
     hdx_spec: dict
     """Dictionary with HDX-MS state specification"""
 
-    metadata: Optional[dict]
+    metadata: Optional[dict] = field(default_factory=dict)
     """Optional metadata"""
 
     _cache: dict[tuple[str, str], pd.DataFrame] = field(init=False, default_factory=dict)