def get_x_minmax(start_times, end_times):
    """Determine the horizontal (x) min and max values.

    This function adds 1% to either side for padding.

    Args:
        start_times (np.array): First packet unix timestamps of all pcaps.
        end_times (np.array): Last packet unix timestamps of all pcaps.
    Returns:
        (tuple): min_x, max_x to be used for graph
    """
    first_time = min(start_times)
    last_time = max(end_times)
    graph_one_percent_width = (last_time - first_time) / 100
    first = first_time - graph_one_percent_width
    last = last_time + graph_one_percent_width
    return first, last
