If the trie is empty then initialize it by applying
        txns from ledger.

def init_state_from_ledger(self, state: State, ledger: Ledger, reqHandler):
        """
        If the trie is empty then initialize it by applying
        txns from ledger.
        """
        if state.isEmpty:
            logger.info('{} found state to be empty, recreating from '
                        'ledger'.format(self))
            for seq_no, txn in ledger.getAllTxn():
                txn = self.update_txn_with_extra_data(txn)
                reqHandler.updateState([txn, ], isCommitted=True)
                state.commit(rootHash=state.headHash)