1 files changed, 5 insertions, 1 deletions
diff --git a/bsie/reader/builder.py b/bsie/reader/builder.py
index bce5397..8699e75 100644
--- a/bsie/reader/builder.py
+++ b/bsie/reader/builder.py
@@ -40,7 +40,11 @@ class ReaderBuilder():
     # cached readers
     _cache: typing.Dict[str, base.Reader]
 
-    def __init__(self, kwargs: typing.Dict[str, typing.Dict[str, typing.Any]]):
+    def __init__(
+            self,
+            kwargs: typing.Optional[typing.Dict[str, typing.Dict[str, typing.Any]]] = None):
+        if kwargs is None:
+            kwargs = {}
         self._kwargs = kwargs
         self._cache = {}