code: func (s *UIServerAPI) SetChainId(id math.HexOrDecimal64) math.HexOrDecimal64 {
  	s.extApi.chainID = new(big.Int).SetUint64(uint64(id))
  	return s.ChainId()
  }
docs: // SetChainId sets the chain id to use when signing transactions.
  // Example call to set Ropsten:
  // {"jsonrpc":"2.0","method":"clef_setChainId","params":["3"], "id":8}