Refs #25629 -- Added `arity` class attribute to `Func` expressions

1 files changed, 9 insertions, 0 deletions

diff --git a/docs/ref/models/expressions.txt b/docs/ref/models/expressions.txt
index 87c3108509..98ba323171 100644
--- a/docs/ref/models/expressions.txt
+++ b/docs/ref/models/expressions.txt
@@ -252,6 +252,15 @@ The ``Func`` API is as follows:
         A class attribute that denotes the character used to join the list of
         ``expressions`` together. Defaults to ``', '``.
 
+    .. attribute:: arity
+
+        .. versionadded:: 1.10
+
+        A class attribute that denotes the number of arguments the function
+        accepts. If this attribute is set and the function is called with a
+        different number of expressions, ``TypeError`` will be raised. Defaults
+        to ``None``.
+
 The ``*expressions`` argument is a list of positional expressions that the
 function will be applied to. The expressions will be converted to strings,
 joined together with ``arg_joiner``, and then interpolated into the ``template``