code: function (funABI, values, contractbyteCode) {
      var encoded
      var encodedHex
      try {
        encoded = helper.encodeParams(funABI, values)
        encodedHex = encoded.toString('hex')
      } catch (e) {
        return { error: 'cannot encode arguments' }
      }
      if (contractbyteCode) {
        return { data: '0x' + contractbyteCode + encodedHex.replace('0x', '') }
      } else {
        return { data: helper.encodeFunctionId(funABI) + encodedHex.replace('0x', '') }
      }
    }
docs: build the transaction data
  
  @param {Object} function abi
  @param {Object} values to encode
  @param {String} contractbyteCode