or download this
Benchmark: timing 1000 iterations of None, Slasho, qr...
None: 30 wallclock secs (30.08 usr + 0.14 sys = 30.22 CPU) @ 33.09/s
Slasho: 29 wallclock secs (28.74 usr + 0.02 sys = 28.76 CPU) @ 34.77/s
qr: 31 wallclock secs (30.49 usr + 0.00 sys = 30.49 CPU) @ 32.80/s