diff --git a/Doc/library/gc.rst b/Doc/library/gc.rst
index 82277aa52ae..e36a71af2b6 100644
--- a/Doc/library/gc.rst
+++ b/Doc/library/gc.rst
@@ -96,7 +96,7 @@ The :mod:`gc` module provides the following functions:
    .. versionadded:: 3.4
 
 
-.. function:: set_threshold(threshold0[, threshold1[, threshold2]])
+.. function:: set_threshold(threshold0, [threshold1, [threshold2]])
 
    Set the garbage collection thresholds (the collection frequency). Setting
    *threshold0* to zero disables collection.
diff --git a/Modules/clinic/gcmodule.c.h b/Modules/clinic/gcmodule.c.h
index ad446935044..d50d170589a 100644
--- a/Modules/clinic/gcmodule.c.h
+++ b/Modules/clinic/gcmodule.c.h
@@ -214,6 +214,58 @@ exit:
     return return_value;
 }
 
+PyDoc_STRVAR(gc_set_threshold__doc__,
+"set_threshold(threshold0, [threshold1, [threshold2]])\n"
+"Set the collection thresholds (the collection frequency).\n"
+"\n"
+"Setting \'threshold0\' to zero disables collection.");
+
+#define GC_SET_THRESHOLD_METHODDEF    \
+    {"set_threshold", (PyCFunction)gc_set_threshold, METH_VARARGS, gc_set_threshold__doc__},
+
+static PyObject *
+gc_set_threshold_impl(PyObject *module, int threshold0, int group_right_1,
+                      int threshold1, int group_right_2, int threshold2);
+
+static PyObject *
+gc_set_threshold(PyObject *module, PyObject *args)
+{
+    PyObject *return_value = NULL;
+    int threshold0;
+    int group_right_1 = 0;
+    int threshold1 = 0;
+    int group_right_2 = 0;
+    int threshold2 = 0;
+
+    switch (PyTuple_GET_SIZE(args)) {
+        case 1:
+            if (!PyArg_ParseTuple(args, "i:set_threshold", &threshold0)) {
+                goto exit;
+            }
+            break;
+        case 2:
+            if (!PyArg_ParseTuple(args, "ii:set_threshold", &threshold0, &threshold1)) {
+                goto exit;
+            }
+            group_right_1 = 1;
+            break;
+        case 3:
+            if (!PyArg_ParseTuple(args, "iii:set_threshold", &threshold0, &threshold1, &threshold2)) {
+                goto exit;
+            }
+            group_right_1 = 1;
+            group_right_2 = 1;
+            break;
+        default:
+            PyErr_SetString(PyExc_TypeError, "gc.set_threshold requires 1 to 3 arguments");
+            goto exit;
+    }
+    return_value = gc_set_threshold_impl(module, threshold0, group_right_1, threshold1, group_right_2, threshold2);
+
+exit:
+    return return_value;
+}
+
 PyDoc_STRVAR(gc_get_threshold__doc__,
 "get_threshold($module, /)\n"
 "--\n"
@@ -250,6 +302,76 @@ gc_get_count(PyObject *module, PyObject *Py_UNUSED(ignored))
     return gc_get_count_impl(module);
 }
 
+PyDoc_STRVAR(gc_get_referrers__doc__,
+"get_referrers($module, /, *objs)\n"
+"--\n"
+"\n"
+"Return the list of objects that directly refer to any of \'objs\'.");
+
+#define GC_GET_REFERRERS_METHODDEF    \
+    {"get_referrers", _PyCFunction_CAST(gc_get_referrers), METH_FASTCALL, gc_get_referrers__doc__},
+
+static PyObject *
+gc_get_referrers_impl(PyObject *module, PyObject *args);
+
+static PyObject *
+gc_get_referrers(PyObject *module, PyObject *const *args, Py_ssize_t nargs)
+{
+    PyObject *return_value = NULL;
+    PyObject *__clinic_args = NULL;
+
+    if (!_PyArg_CheckPositional("get_referrers", nargs, 0, PY_SSIZE_T_MAX)) {
+        goto exit;
+    }
+    __clinic_args = PyTuple_New(nargs - 0);
+    if (!__clinic_args) {
+        goto exit;
+    }
+    for (Py_ssize_t i = 0; i < nargs - 0; ++i) {
+        PyTuple_SET_ITEM(__clinic_args, i, Py_NewRef(args[0 + i]));
+    }
+    return_value = gc_get_referrers_impl(module, __clinic_args);
+
+exit:
+    Py_XDECREF(__clinic_args);
+    return return_value;
+}
+
+PyDoc_STRVAR(gc_get_referents__doc__,
+"get_referents($module, /, *objs)\n"
+"--\n"
+"\n"
+"Return the list of objects that are directly referred to by \'objs\'.");
+
+#define GC_GET_REFERENTS_METHODDEF    \
+    {"get_referents", _PyCFunction_CAST(gc_get_referents), METH_FASTCALL, gc_get_referents__doc__},
+
+static PyObject *
+gc_get_referents_impl(PyObject *module, PyObject *args);
+
+static PyObject *
+gc_get_referents(PyObject *module, PyObject *const *args, Py_ssize_t nargs)
+{
+    PyObject *return_value = NULL;
+    PyObject *__clinic_args = NULL;
+
+    if (!_PyArg_CheckPositional("get_referents", nargs, 0, PY_SSIZE_T_MAX)) {
+        goto exit;
+    }
+    __clinic_args = PyTuple_New(nargs - 0);
+    if (!__clinic_args) {
+        goto exit;
+    }
+    for (Py_ssize_t i = 0; i < nargs - 0; ++i) {
+        PyTuple_SET_ITEM(__clinic_args, i, Py_NewRef(args[0 + i]));
+    }
+    return_value = gc_get_referents_impl(module, __clinic_args);
+
+exit:
+    Py_XDECREF(__clinic_args);
+    return return_value;
+}
+
 PyDoc_STRVAR(gc_get_objects__doc__,
 "get_objects($module, /, generation=None)\n"
 "--\n"
@@ -425,4 +547,4 @@ gc_get_freeze_count(PyObject *module, PyObject *Py_UNUSED(ignored))
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=5c345e7b4ce6085a input=a9049054013a1b77]*/
+/*[clinic end generated code: output=258f92524c1141fc input=a9049054013a1b77]*/
diff --git a/Modules/gcmodule.c b/Modules/gcmodule.c
index 9a827cb79d7..ffddef34ecc 100644
--- a/Modules/gcmodule.c
+++ b/Modules/gcmodule.c
@@ -134,24 +134,41 @@ gc_get_debug_impl(PyObject *module)
     return gcstate->debug;
 }
 
-PyDoc_STRVAR(gc_set_thresh__doc__,
-"set_threshold(threshold0, [threshold1, threshold2]) -> None\n"
-"\n"
-"Sets the collection thresholds.  Setting threshold0 to zero disables\n"
-"collection.\n");
+/*[clinic input]
+gc.set_threshold
+
+    threshold0: int
+    [
+    threshold1: int
+    [
+    threshold2: int
+    ]
+    ]
+    /
+
+Set the collection thresholds (the collection frequency).
+
+Setting 'threshold0' to zero disables collection.
+[clinic start generated code]*/
 
 static PyObject *
-gc_set_threshold(PyObject *self, PyObject *args)
+gc_set_threshold_impl(PyObject *module, int threshold0, int group_right_1,
+                      int threshold1, int group_right_2, int threshold2)
+/*[clinic end generated code: output=2e3c7c7dd59060f3 input=0d9612db50984eec]*/
 {
     GCState *gcstate = get_gc_state();
-    if (!PyArg_ParseTuple(args, "i|ii:set_threshold",
-                          &gcstate->generations[0].threshold,
-                          &gcstate->generations[1].threshold,
-                          &gcstate->generations[2].threshold))
-        return NULL;
-    for (int i = 3; i < NUM_GENERATIONS; i++) {
+
+    gcstate->generations[0].threshold = threshold0;
+    if (group_right_1) {
+        gcstate->generations[1].threshold = threshold1;
+    }
+    if (group_right_2) {
+        gcstate->generations[2].threshold = threshold2;
+
         /* generations higher than 2 get the same threshold */
-        gcstate->generations[i].threshold = gcstate->generations[2].threshold;
+        for (int i = 3; i < NUM_GENERATIONS; i++) {
+            gcstate->generations[i].threshold = gcstate->generations[2].threshold;
+        }
     }
     Py_RETURN_NONE;
 }
@@ -190,12 +207,17 @@ gc_get_count_impl(PyObject *module)
                          gcstate->generations[2].count);
 }
 
-PyDoc_STRVAR(gc_get_referrers__doc__,
-"get_referrers(*objs) -> list\n\
-Return the list of objects that directly refer to any of objs.");
+/*[clinic input]
+gc.get_referrers
+
+    *objs as args: object
+
+Return the list of objects that directly refer to any of 'objs'.
+[clinic start generated code]*/
 
 static PyObject *
-gc_get_referrers(PyObject *self, PyObject *args)
+gc_get_referrers_impl(PyObject *module, PyObject *args)
+/*[clinic end generated code: output=296a09587f6a86b5 input=bae96961b14a0922]*/
 {
     if (PySys_Audit("gc.get_referrers", "(O)", args) < 0) {
         return NULL;
@@ -213,12 +235,17 @@ referentsvisit(PyObject *obj, void *arg)
     return PyList_Append(list, obj) < 0;
 }
 
-PyDoc_STRVAR(gc_get_referents__doc__,
-"get_referents(*objs) -> list\n\
-Return the list of objects that are directly referred to by objs.");
+/*[clinic input]
+gc.get_referents
+
+    *objs as args: object
+
+Return the list of objects that are directly referred to by 'objs'.
+[clinic start generated code]*/
 
 static PyObject *
-gc_get_referents(PyObject *self, PyObject *args)
+gc_get_referents_impl(PyObject *module, PyObject *args)
+/*[clinic end generated code: output=d47dc02cefd06fe8 input=b3ceab0c34038cbf]*/
 {
     Py_ssize_t i;
     if (PySys_Audit("gc.get_referents", "(O)", args) < 0) {
@@ -453,17 +480,15 @@ static PyMethodDef GcMethods[] = {
     GC_SET_DEBUG_METHODDEF
     GC_GET_DEBUG_METHODDEF
     GC_GET_COUNT_METHODDEF
-    {"set_threshold",  gc_set_threshold, METH_VARARGS, gc_set_thresh__doc__},
+    GC_SET_THRESHOLD_METHODDEF
     GC_GET_THRESHOLD_METHODDEF
     GC_COLLECT_METHODDEF
     GC_GET_OBJECTS_METHODDEF
     GC_GET_STATS_METHODDEF
     GC_IS_TRACKED_METHODDEF
     GC_IS_FINALIZED_METHODDEF
-    {"get_referrers",  gc_get_referrers, METH_VARARGS,
-        gc_get_referrers__doc__},
-    {"get_referents",  gc_get_referents, METH_VARARGS,
-        gc_get_referents__doc__},
+    GC_GET_REFERRERS_METHODDEF
+    GC_GET_REFERENTS_METHODDEF
     GC_FREEZE_METHODDEF
     GC_UNFREEZE_METHODDEF
     GC_GET_FREEZE_COUNT_METHODDEF