Error in android wallet build[solved]

Hello Everyone,

I am facing an issue while trying to run/build the android wallet source code in android studio. I downloaded the wallet source code from https://github.com/blockchain-certificates/wallet-android. I imported the code as gradle project and tried to run it, got the following error.
Java Compiler : error: cannot find symbol method verifyIssuer(BlockCert,TxRecord); error: cannot find symbol method verifyBitcoinTransactionRecord(BlockCert) 33%20PM

Also, tried running the build.sh file, and it got failed.

Kindly help me solve the issue.

Note: BTW, I am very new to Blockchain, Android & Java. So, kindly spare me if any.

Thanks,
Gowtham R