public static String buildEventSignature(String methodSignature) {
        byte[] input = methodSignature.getBytes();
        byte[] hash = Hash.sha3(input);
        return Numeric.toHexString(hash);
    }
@Test
    public void testBuildEventSignature() {
        assertEquals(
                EventEncoder.buildEventSignature("Deposit(address,hash256,uint256)"),
                ("0x50cb9fe53daa9737b786ab3646f04d0150dc50ef4e75f59509d83667ad5adb20"));

        assertEquals(
                EventEncoder.buildEventSignature("Notify(uint256,uint256)"),
                ("0x71e71a8458267085d5ab16980fd5f114d2d37f232479c245d523ce8d23ca40ed"));
    }