code: public TransactionWriteRequest addConditionCheck(Object key, DynamoDBTransactionWriteExpression transactionWriteExpression) {
          return addConditionCheck(key, transactionWriteExpression, null /* returnValuesOnConditionCheckFailure */);
      }
docs: Adds conditionCheck operation (to be executed on the object represented by key) to the list of transaction write operations.
  transactionWriteExpression is used to condition check on the object represented by key.