bpo-42528: Improve the docs of most Py*_Check{,Exact} API calls (GH-23602)
I think that none of these API calls can fail, but only few of them are
documented as such. Add the sentence "This function always succeeds" (which is
the same already used e.g. by PyNumber_Check) to all of them.diff --git a/Doc/c-api/slice.rst b/Doc/c-api/slice.rst
index 48a58c6..8271d9a 100644
--- a/Doc/c-api/slice.rst
+++ b/Doc/c-api/slice.rst
@@ -14,7 +14,8 @@
.. c:function:: int PySlice_Check(PyObject *ob)
- Return true if *ob* is a slice object; *ob* must not be ``NULL``.
+ Return true if *ob* is a slice object; *ob* must not be ``NULL``. This
+ function always succeeds.
.. c:function:: PyObject* PySlice_New(PyObject *start, PyObject *stop, PyObject *step)