python reads oracle function return value

Creating a function in Oracle originally wanted to return an index table, but it failed. Thinking that text can also transmit information, I suddenly had the inspiration to set the return value in text format.
Considering that the amount of returned data may be large and the length of the varchar2 type is tight, the return value type is set to clob.
I am using scott user’s test table emp. This is the function definition:

create or replace function test_query_func(dept varchar2)
return clob
is
 type test_record is record
 (rec_empno emp.empno%type,
 rec_ename emp.ename%type,
 rec_job  emp.job%type,
 rec_sal  emp.sal%type);
 type test_query_arr is table of test_record index by binary_integer;
 cursor cur is select empno, ename, job, sal from emp where deptno = dept;
 test_query test_query_arr;
 i integer := 0;
 ss varchar2(200) := '';
 res clob := '[';
begin
 for c in cur loop
  i := i + 1;
  test_query(i) := c;
 end loop;
 for q in 1..test_query.count loop
  ss := '(''' || test_query(q).rec_empno || ''', ''' || test_query(q).rec_ename || ''', ''' || test_query(q).rec_job || ''', ''' || test_query(q).rec_sal || ''')';
 if q < test_query.count then
 ss := ss || ',';
 end if;
 res := res || ss;
 end loop;
 res := res || ']';
 return res;
end;

You can test the return value of this function in pl/sql developer:

 begin
 dbms_output.put_line(test_query_func('30'));
 end; 

Output result:
[('7499', 'ALLEN', 'SALESMAN', '1600'),('7521', 'WARD', 'SALESMAN', '1250'),('7654', 'MARTIN', 'SALESMAN' , '1250'),('7698', 'BLAKE', 'MANAGER', '2850'),('7844', 'TURNER', 'SALESMAN', '1500'),('7900', 'JAMES' , 'CLERK', '950')]
In fact, it has been defined as a style that contains tuple sub-elements in a list in python.
The following is the code in python. Using python to connect to oracle requires the cx_Oracle library:

import cx_Oracle as ora;
con = ora.connect('scott/scott@oradb');
cur = con.cursor();
cur.execute('select test_query_func(30) from dual');
res = cur.fetchall()[0][0].read();
cur.close();
con.close();
data = eval(res);
import pandas as pd;
df = pd.DataFrame(data, columns = ['empno', 'ename', 'job', 'sal']);
print(df)

In this way, the long string value returned by the function in Oracle is converted into a DataFrame object:

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