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/iterator.rst b/Doc/c-api/iterator.rst
index 4d91e4a..3fcf099 100644
--- a/Doc/c-api/iterator.rst
+++ b/Doc/c-api/iterator.rst
@@ -21,7 +21,8 @@
.. c:function:: int PySeqIter_Check(op)
- Return true if the type of *op* is :c:data:`PySeqIter_Type`.
+ Return true if the type of *op* is :c:data:`PySeqIter_Type`. This function
+ always succeeds.
.. c:function:: PyObject* PySeqIter_New(PyObject *seq)
@@ -39,7 +40,8 @@
.. c:function:: int PyCallIter_Check(op)
- Return true if the type of *op* is :c:data:`PyCallIter_Type`.
+ Return true if the type of *op* is :c:data:`PyCallIter_Type`. This
+ function always succeeds.
.. c:function:: PyObject* PyCallIter_New(PyObject *callable, PyObject *sentinel)