bpo-37942: Improve argument clinic float converter by rhettinger · Pull Request #15470 · python/cpython

Baseline timing:
./python.exe -m timeit -r11 -s 'from statistics import _normal_dist_inv_cdf as f' -s 't=0.75,0.0,1.0' 'f(*t)'
5000000 loops, best of 11: 61.1 nsec per loop

Improved timing:
./python.exe -m timeit -r11 -s 'from statistics import _normal_dist_inv_cdf as f' -s 't=0.75,0.0,1.0' 'f(*t)'
5000000 loops, best of 11: 52.5 nsec per loop