docs: def _rsfx_count(oracle, s, count, hist, ab):
      """ Accumulate counts for context """
  
      trn_data = [oracle.data[n] for n in oracle.trn[s]]
      for k in trn_data:
          hist[ab[k]] += 1.0
          count += 1.0
  
      rsfx_candidate = oracle.rsfx[s][:]
      while rsfx_candidate:
          s = rsfx_candidate.pop(0)
          trn_data = [oracle.data[n] for n in oracle.trn[s]]
          for k in trn_data:
              hist[ab[k]] += 1.0
              count += 1.0
          rsfx_candidate.extend(oracle.rsfx[s])
  
      return count, hist