def randomWalkFunction(requestContext, name, step=60):
    """
    Short Alias: randomWalk()

    Returns a random walk starting at 0. This is great for testing when there
    is no real data in whisper.

    Example::

        &target=randomWalk("The.time.series")

    This would create a series named "The.time.series" that contains points
    where x(t) == x(t-1)+random()-0.5, and x(0) == 0.

    Accepts an optional second argument as step parameter (default step is
    60 sec).
    """
    delta = timedelta(seconds=step)
    when = requestContext["startTime"]
    values = []
    current = 0
    while when < requestContext["endTime"]:
        values.append(current)
        current += random.random() - 0.5
        when += delta

    return [TimeSeries(
        name, int(epoch(requestContext["startTime"])),
        int(epoch(requestContext["endTime"])),
        step, values)]

    Short Alias: randomWalk()

    Returns a random walk starting at 0. This is great for testing when there
    is no real data in whisper.

    Example::

        &target=randomWalk("The.time.series")

    This would create a series named "The.time.series" that contains points
    where x(t) == x(t-1)+random()-0.5, and x(0) == 0.

    Accepts an optional second argument as step parameter (default step is
    60 sec).
    
graphite_api/functions.py