rotate.py

import math

def rotate(array, steps):
    steps = steps % len(array)
    reverse(array, 0, len(array) - 1)
    reverse(array, 0, steps - 1)
    reverse(array, steps, len(array) - 1)
    return array

def reverse(array, start, end):
    for x in range(math.ceil(((float(end) - float(start)) / 2))):
        temp = array[start + x]
        array[start + x] = array[end - x]
        array[end - x] = temp
    return array