From 2882cd207831c2b9b4751e258493db109e5f3d66 Mon Sep 17 00:00:00 2001
From: Yixiao Chen <chen_yixiao@outlook.com>
Date: Sat, 1 Jan 2022 03:25:31 -0600
Subject: [PATCH] fix bug in json, add anydict example

---
 dargs/dargs.py        | 6 ++++--
 tests/test_checker.py | 6 +++++-
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/dargs/dargs.py b/dargs/dargs.py
index 4ab2a96..6663c8b 100644
--- a/dargs/dargs.py
+++ b/dargs/dargs.py
@@ -657,18 +657,20 @@ def default(self, obj) -> Dict[str, Union[str, bool, List]]:
             a dict containing argument information
         """
         if isinstance(obj, Argument):
-            return {
+            output = {
                 "object": "Argument",
                 "name": obj.name,
                 "type": obj.dtype,
                 "optional": obj.optional,
-                "default": obj.default,
                 "alias": obj.alias,
                 "doc": obj.doc,
                 "repeat": obj.repeat,
                 "sub_fields": obj.sub_fields,
                 "sub_variants": obj.sub_variants,
             }
+            if obj.optional and obj.default is not _Flags.NONE:
+                output['default'] = obj.default
+            return output
         elif isinstance(obj, Variant):
             return {
                 "object": "Variant",
diff --git a/tests/test_checker.py b/tests/test_checker.py
index 692cc03..a294d52 100644
--- a/tests/test_checker.py
+++ b/tests/test_checker.py
@@ -32,7 +32,11 @@ def test_name_type(self):
         ca.check({"key1": 1})
         with self.assertRaises(ArgumentValueError):
             ca.check({"key1": 0})
-
+        # check any keywords
+        ca = Argument("kwargs", dict)
+        anydict = {"this": 1, "that": 2, "any": 3}
+        ca.check({"kwargs": anydict})
+        ca.check_value(anydict)
 
     def test_sub_fields(self):
         ca = Argument("base", dict, [