Added documentation for PyFunction_GetAnnotations() and

PyFunction_SetAnnotations().

Doc/c-api/function.rst

@@ -81,3 +81,15 @@ There are a few functions specific to Python functions.
    *Py_None* or a tuple of cell objects.
 
    Raises :exc:`SystemError` and returns ``-1`` on failure.
+
+
+.. cfunction:: PyObject *PyFunction_GetAnnotations(PyObject *op)
+
+   Return the annotations of the function object *op*. This can be a
+   mutable dictionary or *NULL*.
+
+
+.. cfunction:: int PyFunction_SetAnnotations(PyObject *op, PyObject *annotations)
+
+   Set the annotations for the function object *op*. *annotations*
+   must be a dictionary or *Py_None*.