SQL & PL/SQL

Hi all,
I have a function as follows:

FUNCTION is_Valid_Segments(cm_no varchar2, pm varchar2)
    RETURN BOOLEAN
    IS
    CURSOR seg_cursor IS
    SELECT product_manager,sales_in_segments
    FROM temp_product_details
    WHERE   cm_ticket_no=cm_no;
    BEGIN
        FOR seg_rec IN seg_cursor
        LOOP
            IF (TRIM(seg_rec.sales_in_segment) = TRIM(pm))  THEN
                RETURN TRUE;
            END IF;
        END LOOP;
        RETURN FALSE;
    END;

In the above code i return in between the loop if the condition is satisfied. So does this leave the Cursor open and occupy memory ?
If so how can i close the cursor before the return statement?