def best_and_worst_hour(percentages):
    """

    Args:
    percentages: output of compute_percentage
    Return: list of strings, the first element should be the best hour,
    the second (and last) element should be the worst hour. Hour are
    represented by string with format %H:%M
    e.g. ["18:00", "20:00"]

    """
    #position [0] returns: profit = 0, and [1] returns time
    hora = 1

    # Calculate the best and worst hour:
    bestHour = max(zip(percentages.values(), percentages.keys()))
    worstHour = min(zip(percentages.values(), percentages.keys()))

    return [bestHour[hora], worstHour[hora]]