code: def _ensure_like_indices(time, panels):
      
      n_time = len(time)
      n_panel = len(panels)
      u_panels = np.unique(panels)  # this sorts!
      u_time = np.unique(time)
      if len(u_time) == n_time:
          time = np.tile(u_time, len(u_panels))
      if len(u_panels) == n_panel:
          panels = np.repeat(u_panels, len(u_time))
      return time, panels
docs: Makes sure that time and panels are conformable.