# credit author(s) of random.py
import random
def sample_wr(population, k):
"Chooses k random elements (with replacement) from a population"
n = len(population)
_random, _int = random.random, int # speed hack
result = [None] * k
for i in xrange(k):
j = _int(_random() * n)
result[i] = population[j]
return result