def split_reaches(l, new_reach_pts):
    """splits l into sections where new_reach_pts contains the starting indices for each slice"""
    new_reach_pts = sorted(new_reach_pts)
    sl = [l[i1:i2] for i1, i2 in zip(new_reach_pts, new_reach_pts[1:])]
    last_index = new_reach_pts[-1]
    sl.append(l[last_index:])
    return sl