How to fortify fetchone sentence in desktop aplication?

Question

Guys I need to fortify (Scan code analysis) the following script:

 def _insert_s_s(self, curr, s_d, usu):
        if usu[0:7]=='user':
            curr.execute('''INSERT INTO shema1.table1(D_T, D_B, S_T, F, E, ID_W) VALUES(%s, %s, %s, %s, %s, %s) RETURNING ID_S''', s_d)
            retval = curr.fetchone()[0]
        return retval

But after fortify the code I get the message:

Database access control errors occur when:

Data enters a program from an untrusted source.

In this case, the data enters at fetchone() in cgtransaction.py on line 154.

And in the following code:

def _insert_file_c(self, curr, f_d, usu):
        if usu[0:7]=='usersgc':
            curr.execute('''INSERT INTO shema3.table3(F_T, ID_F, ID_S) VALUES (%s, %s, %s)''', f_d)

I get the message:

The data is used to specify the value of a primary key in a SQL query.

In this case, the data is used by execute() in cgtransaction.py on line 175.

Please let me know if you have some ideas. Thanks a lot.