code: function signTransaction(priKeyBytes, transaction) {
  
    if (typeof priKeyBytes === 'string') {
      priKeyBytes = hexStr2byteArray(priKeyBytes);
    }
  
    let raw = transaction.getRawData();
    let rawBytes = raw.serializeBinary();
    let hashBytes = SHA256(rawBytes);
    let signBytes = ECKeySign(hashBytes, priKeyBytes);
    let uint8Array = new Uint8Array(signBytes);
    let count = raw.getContractList().length;
    for (let i = 0; i < count; i++) {
      transaction.addSignature(uint8Array);
    }
  
    return transaction;
  }
docs: a0 + address  ,a0 is version 
  Sign A Transaction by priKey.
  signature is 65 bytes, r[32] || s[32] || id[1](<27)
  
  @returns  a Transaction object signed
  @param priKeyBytes: privateKey for ECC
  @param transaction: a Transaction object unSigned