diff -r 593ec9658f4b Modules/_bisectmodule.c
--- a/Modules/_bisectmodule.c	Sun Nov 20 17:43:09 2016 +0200
+++ b/Modules/_bisectmodule.c	Sun Nov 20 17:55:01 2016 +0100
@@ -6,6 +6,13 @@
 #define PY_SSIZE_T_CLEAN
 #include "Python.h"
 
+#include "clinic/_bisectmodule.c.h"
+
+/*[clinic input]
+module bisect
+[clinic start generated code]*/
+/*[clinic end generated code: output=da39a3ee5e6b4b0d input=d0e256c42a9e4c13]*/
+
 _Py_IDENTIFIER(insert);
 
 static Py_ssize_t
@@ -148,36 +155,42 @@
     return lo;
 }
 
+/*[clinic input]
+bisect.bisect_left
+
+    a: 'O'
+      The list in which insertion is to be located.
+    x: 'O'
+      The value to be inserted.
+    lo: 'n' = 0
+      Lower bound, defaults to 0.
+    hi: 'n' = -1
+      Upper bound, defaults to -1 (meaning len(a)).
+
+Return the index where to insert item x in list a, assuming a is sorted.
+
+The return value i is such that all e in a[:i] have e < x, and all e in
+a[i:] have e >= x.  So if x already appears in the list, i points just
+before the leftmost x already there.
+
+Optional args lo (default 0) and hi (default len(a)) bound the
+slice of a to be searched.
+
+[clinic start generated code]*/
+
 static PyObject *
-bisect_left(PyObject *self, PyObject *args, PyObject *kw)
+bisect_bisect_left_impl(PyObject *module, PyObject *a, PyObject *x,
+                        Py_ssize_t lo, Py_ssize_t hi)
+/*[clinic end generated code: output=27a0228c4a0a5fa2 input=f936a16dd9bc1bcd]*/
 {
-    PyObject *list, *item;
-    Py_ssize_t lo = 0;
-    Py_ssize_t hi = -1;
     Py_ssize_t index;
-    static char *keywords[] = {"a", "x", "lo", "hi", NULL};
 
-    if (!PyArg_ParseTupleAndKeywords(args, kw, "OO|nn:bisect_left",
-        keywords, &list, &item, &lo, &hi))
-        return NULL;
-    index = internal_bisect_left(list, item, lo, hi);
+    index = internal_bisect_left(a, x, lo, hi);
     if (index < 0)
         return NULL;
     return PyLong_FromSsize_t(index);
 }
 
-PyDoc_STRVAR(bisect_left_doc,
-"bisect_left(a, x[, lo[, hi]]) -> index\n\
-\n\
-Return the index where to insert item x in list a, assuming a is sorted.\n\
-\n\
-The return value i is such that all e in a[:i] have e < x, and all e in\n\
-a[i:] have e >= x.  So if x already appears in the list, i points just\n\
-before the leftmost x already there.\n\
-\n\
-Optional args lo (default 0) and hi (default len(a)) bound the\n\
-slice of a to be searched.\n");
-
 static PyObject *
 insort_left(PyObject *self, PyObject *args, PyObject *kw)
 {
@@ -228,8 +241,7 @@
         METH_VARARGS|METH_KEYWORDS, insort_right_doc},
     {"insort", (PyCFunction)insort_right,
         METH_VARARGS|METH_KEYWORDS, insort_doc},
-    {"bisect_left", (PyCFunction)bisect_left,
-        METH_VARARGS|METH_KEYWORDS, bisect_left_doc},
+    BISECT_BISECT_LEFT_METHODDEF
     {"insort_left", (PyCFunction)insort_left,
         METH_VARARGS|METH_KEYWORDS, insort_left_doc},
     {NULL, NULL} /* sentinel */
diff -r 593ec9658f4b Modules/clinic/_bisectmodule.c.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Modules/clinic/_bisectmodule.c.h	Sun Nov 20 17:55:01 2016 +0100
@@ -0,0 +1,54 @@
+/*[clinic input]
+preserve
+[clinic start generated code]*/
+
+PyDoc_STRVAR(bisect_bisect_left__doc__,
+"bisect_left($module, /, a, x, lo=0, hi=-1)\n"
+"--\n"
+"\n"
+"Return the index where to insert item x in list a, assuming a is sorted.\n"
+"\n"
+"  a\n"
+"    The array in which insertion is desired.\n"
+"  x\n"
+"    The value to be inserted.\n"
+"  lo\n"
+"    Lower bound.\n"
+"  hi\n"
+"    Upper bound.\n"
+"\n"
+"The return value i is such that all e in a[:i] have e < x, and all e in\n"
+"a[i:] have e >= x.  So if x already appears in the list, i points just\n"
+"before the leftmost x already there.\n"
+"\n"
+"Optional args lo (default 0) and hi (default len(a)) bound the\n"
+"slice of a to be searched.");
+
+#define BISECT_BISECT_LEFT_METHODDEF    \
+    {"bisect_left", (PyCFunction)bisect_bisect_left, METH_FASTCALL, bisect_bisect_left__doc__},
+
+static PyObject *
+bisect_bisect_left_impl(PyObject *module, PyObject *a, PyObject *x,
+                        Py_ssize_t lo, Py_ssize_t hi);
+
+static PyObject *
+bisect_bisect_left(PyObject *module, PyObject **args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    static const char * const _keywords[] = {"a", "x", "lo", "hi", NULL};
+    static _PyArg_Parser _parser = {"OO|nn:bisect_left", _keywords, 0};
+    PyObject *a;
+    PyObject *x;
+    Py_ssize_t lo = 0;
+    Py_ssize_t hi = -1;
+
+    if (!_PyArg_ParseStack(args, nargs, kwnames, &_parser,
+        &a, &x, &lo, &hi)) {
+        goto exit;
+    }
+    return_value = bisect_bisect_left_impl(module, a, x, lo, hi);
+
+exit:
+    return return_value;
+}
+/*[clinic end generated code: output=73e63d590f621517 input=a9049054013a1b77]*/