The common case for bisect calls is to have two positional arguments and no keyword arguments.  For this case, PyArg_ParseTupleAndKeywords() is unnecessarily expensive.

Timings
-------

$ pytime -r 11 -s 'from bisect import bisect' -s 'arr=list(range(5))' 'bisect(arr, 2)'
2000000 loops, best of 11: 152 nsec per loop
$ pytime -r 11 -s 'from bisect import bisect' -s 'arr=list(range(5))' 'bisect(arr, 2)'
2000000 loops, best of 11: 152 nsec per loop
$ pytime -r 11 -s 'from bisect import bisect' -s 'arr=list(range(5))' 'bisect(arr, 2)'
2000000 loops, best of 11: 152 nsec per loop

------- patched --------
$ pytime -r 11 -s 'from bisect import bisect' -s 'arr=list(range(5))' 'bisect(arr, 2)'
2000000 loops, best of 11: 112 nsec per loop
$ pytime -r 11 -s 'from bisect import bisect' -s 'arr=list(range(5))' 'bisect(arr, 2)'
2000000 loops, best of 11: 113 nsec per loop
$ pytime -r 11 -s 'from bisect import bisect' -s 'arr=list(range(5))' 'bisect(arr, 2)'
2000000 loops, best of 11: 113 nsec per loop