diff --git a/excore/config/models.py b/excore/config/models.py
index bf46b35..0b0b58f 100644
--- a/excore/config/models.py
+++ b/excore/config/models.py
@@ -322,7 +322,7 @@ def __repr__(self) -> str:
 }
 
 
-def register_special_flag(flag: str, target_module: ModuleNode, force: bool = False) -> None:
+def register_special_flag(flag: str, target_module: NodeType, force: bool = False) -> None:
     if not force and flag in SPECIAL_FLAGS:
         raise ValueError(f"Special flag `{flag}` already exist.")
     SPECIAL_FLAGS.append(flag)
diff --git a/tests/configs/launch/test_module_registry.toml b/tests/configs/launch/test_module_registry.toml
new file mode 100644
index 0000000..83365ed
--- /dev/null
+++ b/tests/configs/launch/test_module_registry.toml
@@ -0,0 +1,7 @@
+[Model.FCN]
+*classifier = "$Head"
+backbone = "$resnet"
+
+[Head.FCNHead]
+in_channels = 512
+channels = 10
diff --git a/tests/test_module_node_registry.py b/tests/test_module_node_registry.py
new file mode 100644
index 0000000..e3597af
--- /dev/null
+++ b/tests/test_module_node_registry.py
@@ -0,0 +1,22 @@
+from excore.config import ModuleNode, load, register_special_flag
+
+
+class FoolModuleNode(ModuleNode):
+    priority = 2
+
+    def __call__(self, **params):
+        p = {}
+        for k, v in self.items():
+            if isinstance(v, int):
+                v += 1
+            p[k] = v
+        return super().__call__(**p)
+
+
+register_special_flag("*", FoolModuleNode)
+
+
+def test_module_node_registry():
+    cfg = load("./configs/launch/test_module_registry.toml")
+    module, info = cfg.build_all()
+    assert module.Model.classifier[0].in_channels == 513