New in version 1.1.1.
Interlace elements of arbirarily many iterables.
k = range(100, 103)
l = range(200, 201)
m = range(300, 303)
n = range(400, 408)
t = listtools.interlace(k, l, m, n)
[100, 200, 300, 400, 101, 301, 401, 102, 302, 402, 403, 404, 405, 406, 407]