implement power method

[xgbuils]

I would like to implement a power method that do the cartesian product of an iterable n times:

Iterum([0, 1]).power(3) /* (
    (0 0 0)
    (1 0 0)
    (0 1 0)
    (1 1 0)
    (0 0 1)
    (1 0 1)
    (0 1 1)
    (1 1 1)
) */ 

This method produces the same result like:

Iterum.product([0, 1], [0, 1], [0, 1])

However, Iterum.product cannot produce a cartesian product of infinite iterables and Iterum.power can.

Iterum([0, 1]).power(Infinity) /* (
    (0, 0, 0, 0, 0, ...)
    (1, 0, 0, 0, 0, ...)
    (0, 1, 0, 0, 0, ...)
    (1, 1, 0, 0, 0, ...)
    ...
) */