Oracle Apex Clob display column throwing error for null value

I have an Interactive Grid in Apex where i need to dispaly clob column.

I followed the below link and set up exactly till step 10.

It works fine if there is data. But in case of null it throws PL/SQL numeric error.

How can this be handled?

https://akilramesh.blogspot.com/2021/06/display-and-edit-clob-content-in-oracle.html

Wrap the loop in an IF statement to check that the CLOB is not null:

DECLARE
  LO_CLOB        CLOB;
  LO_CHUNK_SIZE  NUMBER := 4000;
BEGIN
  SELECT DESCRIPTION 
  INTO   LO_CLOB 
  FROM   T_EMPLOYEE
  WHERE  EMP_ID = apex_application.g_x01;

  IF lo_clob IS NOT NULL THEN
    FOR i IN 0 .. FLOOR(LENGTH(LO_CLOB)/LO_CHUNK_SIZE )
    LOOP
      SYS.HTP.PRN(SUBSTR(LO_CLOB, i * LO_CHUNK_SIZE + 1, LO_CHUNK_SIZE ));
    END LOOP;
  END IF;
END;
/

fiddle