diff --git a/sepes/_src/tree_mask.py b/sepes/_src/tree_mask.py
index d6a582c..482975f 100644
--- a/sepes/_src/tree_mask.py
+++ b/sepes/_src/tree_mask.py
@@ -172,37 +172,10 @@ def _(value: _MaskBase[T]) -> T:
 
 
 def is_nondiff(value: Any) -> bool:
-    """Returns True for non-inexact types, False otherwise.
-
-    Args:
-        value: A value to check.
-
-    Note:
-        - :func:`.is_nondiff` uses single dispatch to support custom types. To define
-          a custom behavior for a certain type, use ``is_nondiff.def_type(type, func)``.
-
-    Example:
-        >>> import sepes as sp
-        >>> import jax.numpy as jnp
-        >>> sp.is_nondiff(jnp.array(1))  # int array is non-diff type
-        True
-        >>> sp.is_nondiff(jnp.array(1.))  # float array is diff type
-        False
-        >>> sp.is_nondiff(1)  # int is non-diff type
-        True
-        >>> sp.is_nondiff(1.)  # float is diff type
-        False
-
-    Note:
-        This function is meant to be used with ``jax.tree_map`` to
-        create a mask for non-differentiable nodes in a tree, that can be used
-        to freeze the non-differentiable nodes before passing the tree to a
-        ``jax`` transformation.
-    """
     return is_nondiff.type_dispatcher(value)
 
 
-is_nondiff.type_dispatcher = ft.singledispatch(lambda x: True)
+is_nondiff.type_dispatcher = ft.singledispatch(lambda _: True)
 is_nondiff.def_type = is_nondiff.type_dispatcher.register
 
 
@@ -261,8 +234,8 @@ def tree_mask(
     Args:
         tree: A pytree of values.
         cond: A callable that accepts a leaf and returns a boolean to mark the leaf
-            for masking. Defaults to masking non-differentiable leaf nodes that 
-            are not instances of of python float, python complex, or inexact 
+            for masking. Defaults to masking non-differentiable leaf nodes that
+            are not instances of of python float, python complex, or inexact
             array types.
         is_leaf: A callable that accepts a leaf and returns a boolean. If
             provided, it is used to determine if a value is a leaf. for example,