startswith and endswith don't accept None as slice index

Objects/bytesobject.c

 /* bytes object implementation */
 
 #define PY_SSIZE_T_CLEAN
 
 #include "Python.h"
 
 #include "bytes_methods.h"
 #include <stddef.h>
 
 static Py_ssize_t
@@ skipping 1549 matching lines @@
         *start = 0;
 }
 
 Py_LOCAL_INLINE(Py_ssize_t)
 bytes_find_internal(PyBytesObject *self, PyObject *args, int dir)
 {
     PyObject *subobj;
     const char *sub;
     Py_ssize_t sub_len;
     Py_ssize_t start=0, end=PY_SSIZE_T_MAX;
-    PyObject *obj_start=Py_None, *obj_end=Py_None;
 
-    if (!PyArg_ParseTuple(args, "O|OO:find/rfind/index/rindex", &subobj,
-        &obj_start, &obj_end))
-        return -2;
-    /* To support None in "start" and "end" arguments, meaning
-       the same as if they were not passed.
-    */
-    if (obj_start != Py_None)
-        if (!_PyEval_SliceIndex(obj_start, &start))
-        return -2;
-    if (obj_end != Py_None)
-        if (!_PyEval_SliceIndex(obj_end, &end))
+    if (!stringlib_parse_args_finds("find/rfind/index/rindex",
+                                    args, &subobj, &start, &end))
         return -2;
 
     if (PyBytes_Check(subobj)) {
         sub = PyBytes_AS_STRING(subobj);
         sub_len = PyBytes_GET_SIZE(subobj);
     }
     else if (PyObject_AsCharBuffer(subobj, &sub, &sub_len))
         /* XXX - the "expected a character buffer object" is pretty
            confusing for a non-expert.  remap to something else ? */
         return -2;
@@ skipping 226 matching lines @@
 as in slice notation.");
 
 static PyObject *
 bytes_count(PyBytesObject *self, PyObject *args)
 {
     PyObject *sub_obj;
     const char *str = PyBytes_AS_STRING(self), *sub;
     Py_ssize_t sub_len;
     Py_ssize_t start = 0, end = PY_SSIZE_T_MAX;
 
-    if (!PyArg_ParseTuple(args, "O|O&O&:count", &sub_obj,
-        _PyEval_SliceIndex, &start, _PyEval_SliceIndex, &end))
+    if (!stringlib_parse_args_finds("count", args, &sub_obj, &start, &end))
         return NULL;
 
     if (PyBytes_Check(sub_obj)) {
         sub = PyBytes_AS_STRING(sub_obj);
         sub_len = PyBytes_GET_SIZE(sub_obj);
     }
     else if (PyObject_AsCharBuffer(sub_obj, &sub, &sub_len))
         return NULL;
 
     bytes_adjust_indices(&start, &end, PyBytes_GET_SIZE(self));
@@ skipping 800 matching lines @@
 prefix can also be a tuple of bytes to try.");
 
 static PyObject *
 bytes_startswith(PyBytesObject *self, PyObject *args)
 {
     Py_ssize_t start = 0;
     Py_ssize_t end = PY_SSIZE_T_MAX;
     PyObject *subobj;
     int result;
 
-    if (!PyArg_ParseTuple(args, "O|O&O&:startswith", &subobj,
-        _PyEval_SliceIndex, &start, _PyEval_SliceIndex, &end))
+    if (!stringlib_parse_args_finds("startswith", args, &subobj, &start, &end))
         return NULL;
     if (PyTuple_Check(subobj)) {
         Py_ssize_t i;
         for (i = 0; i < PyTuple_GET_SIZE(subobj); i++) {
             result = _bytes_tailmatch(self,
                             PyTuple_GET_ITEM(subobj, i),
                             start, end, -1);
             if (result == -1)
                 return NULL;
             else if (result) {
@@ skipping 19 matching lines @@
 suffix can also be a tuple of bytes to try.");
 
 static PyObject *
 bytes_endswith(PyBytesObject *self, PyObject *args)
 {
     Py_ssize_t start = 0;
     Py_ssize_t end = PY_SSIZE_T_MAX;
     PyObject *subobj;
     int result;
 
-    if (!PyArg_ParseTuple(args, "O|O&O&:endswith", &subobj,
-        _PyEval_SliceIndex, &start, _PyEval_SliceIndex, &end))
+    if (!stringlib_parse_args_finds("endswith", args, &subobj, &start, &end))
         return NULL;
     if (PyTuple_Check(subobj)) {
         Py_ssize_t i;
         for (i = 0; i < PyTuple_GET_SIZE(subobj); i++) {
             result = _bytes_tailmatch(self,
                             PyTuple_GET_ITEM(subobj, i),
                             start, end, +1);
             if (result == -1)
                 return NULL;
             else if (result) {
@@ skipping 763 matching lines @@
     }
     it = PyObject_GC_New(striterobject, &PyBytesIter_Type);
     if (it == NULL)
         return NULL;
     it->it_index = 0;
     Py_INCREF(seq);
     it->it_seq = (PyBytesObject *)seq;
     _PyObject_GC_TRACK(it);
     return (PyObject *)it;
 }