def _find_largest_segment(segments):
    """Find the largest segment given a list of start and end
    indices of segments

    Args:
        segments: a list of start and end indices

    Returns:
        longest_segment: the start and end indices of the longest segment

    """
    segment_list = zip(segments[:-1], segments[1:])
    return max(segment_list, key=lambda x: x[1] - x[0])