diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 8d33cad..c22bb77 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -17,6 +17,14 @@ repos:
         args: [pipda]
         types: [python]
         language: system
+    -   id: mypy
+        name: Run mypy
+        files: ^pipda/.+$
+        pass_filenames: false
+        entry: mypy
+        args: [-p, pipda]
+        types: [python]
+        language: system
     -   id: versionchecker
         name: Check version agreement in pyproject and __version__
         entry: bash -c
diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index daa21f7..0d6ca0d 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Change Log
 
+## 0.8.1
+
+- ✨ Allow verb to be a placeholder (without any types registered)
+- ✅ Add test for npufuncs to be used in verbs
+
 ## 0.8.0
 
 - patch classes if they have piping operator method
diff --git a/pipda/__init__.py b/pipda/__init__.py
index 6d75d80..71d7768 100644
--- a/pipda/__init__.py
+++ b/pipda/__init__.py
@@ -12,4 +12,4 @@
 )
 from .piping import register_piping
 
-__version__ = "0.8.0"
+__version__ = "0.8.1"
diff --git a/pipda/verb.py b/pipda/verb.py
index 87a1562..3ef21fa 100644
--- a/pipda/verb.py
+++ b/pipda/verb.py
@@ -141,8 +141,9 @@ def generic(__data, *args, **kwargs):
             self._generic = generic
 
         wrapped = singledispatch(self._generic)
-        update_wrapper(self, func)
-        update_wrapper(wrapped, func)
+        if callable(func):
+            update_wrapper(self, func)
+            update_wrapper(wrapped, func)
         update_user_wrapper(
             self,
             name=name,
@@ -160,7 +161,8 @@ def generic(__data, *args, **kwargs):
 
         if types is not None:
             for t in types:
-                wrapped.register(t, func)
+                if callable(func):
+                    wrapped.register(t, func)
 
         self.func = wrapped
         self.registry = wrapped.registry
@@ -239,9 +241,22 @@ def register_verb(
     """Register a verb
 
     Args:
+        func: The function works as a verb.
+            If `None`, this function will return a decorator.
+            If non-callable, an auto-generated generic function that
+            raises `NotImplementedError()` will be used. This is useful when
+            you want to register a verb as a placeholder. We may not know
+            which types will come in. We can register the types later using
+            `Verb.register()`.
         types: The types of the data allowed to pipe in
             If `None`, then `func` is a generic function instead of an
             automatically created one to raise `NotImplementedError` by default
+            You can also use `object` to register a function, then any type
+            will be registered.
+            >>> f = register_verb(object, func=lambda x: x)
+            >>> f.registered(int)  # True
+            >>> g = register_verb(None, func=lambda x: x)
+            >>> g.registered(int)  # False
         context: The context to evaluate the arguments
         extra_contexts: Extra contexts to evaluate the keyword arguments
         name: and
@@ -265,7 +280,6 @@ def register_verb(
             piping_warning - Suppose piping call, but show a warning
             normal_warning - Suppose normal call, but show a warning
             raise - Raise an error
-        func: The function works as a verb.
     """
     if func is None:
         return lambda fun: register_verb(  # type: ignore
diff --git a/pyproject.toml b/pyproject.toml
index ba38a54..d054064 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "pipda"
-version = "0.8.0"
+version = "0.8.1"
 readme = "README.md"
 description = "A framework for data piping in python"
 authors = ["pwwang <pwwang@pwwang.com>"]
diff --git a/tests/test_verb.py b/tests/test_verb.py
index af73c0f..211c083 100644
--- a/tests/test_verb.py
+++ b/tests/test_verb.py
@@ -225,6 +225,12 @@ def sum2(x):
     assert sum2.registered(int)
 
 
+def test_register_non_callable():
+
+    fun = register_verb(None, func="none")
+    assert not fun.registered(object)
+
+
 def test_types_none():
 
     @register_verb(None)
@@ -291,3 +297,16 @@ def sum2(data, n):
 
     s = np.array([1, 2, 3]) >> sum2(1)
     assert s == 7 and isinstance(s, np.integer)
+
+
+def test_npufunc_as_verb_args():
+
+    f = Symbolic()
+
+    @register_verb(np.ndarray, context=Context.EVAL)
+    def add(data, n):
+        return data + n
+
+    out = np.array([1, -2, 3]) >> add(np.abs(f[1]))
+    out = list(out)
+    assert out == [3, 0, 5] and isinstance(out, list)