code: func indexForNodesWithHashPrefix(key []byte) []byte {
  	return append([]byte{indexForHashesByNodePrefix}, append([]byte(common.Bytes2Hex(key)), keyTermByte)...)
  }
docs: // indexForNodesWithHashPrefix returns a prefix containing a key used in
  // KeyNodes method. Key is hex encoded to be able to use keyTermByte
  // for splitting key and node address.