docs: def apply_t0(self, hits):
          """Apply only t0s"""
          if HAVE_NUMBA:
              apply_t0_nb(
                  hits.time, hits.dom_id, hits.channel_id, self._lookup_tables
              )
          else:
              n = len(hits)
              cal = np.empty(n)
              lookup = self._calib_by_dom_and_channel
              for i in range(n):
                  calib = lookup[hits['dom_id'][i]][hits['channel_id'][i]]
                  cal[i] = calib[6]
              hits.time += cal
          return hits