def get_cont_intervals(indices_list):
    """
    Split a list of indices into sublist of "continous" indices, i.e. indices with difference of 1

    >>> l = [1,2,3,4,8,9,10,20,21,23,29,34,35]
    >>> get_cont_intervals(l)
    [[1, 2, 3, 4], [8, 9, 10], [20, 21], [23], [29], [34, 35]]
    """
    intervals = []
    if len(indices_list) == 0:
        return []
    current_item = indices_list[0]
    inter = [current_item]
    for next_item in indices_list[1:]:
        if next_item == current_item + 1:
            inter.append(next_item)
        else:
            intervals.append(inter)
            inter = [next_item]
        current_item = next_item
    if len(inter) > 0:
        intervals.append(inter)
    return intervals