Oracle report all users, their roles and privileges

I took the sql for listing privileges recursively for Oracle users from Rene Nyffenegger's site, it is very good but only works for one user at a time as it stands, I wanted to run a report that outputted the same way for every user in my database.  So it needed to go into a PL/SQL loop.

set serveroutput on

declare

TYPE re_type IS TABLE OF varchar2(1024);
v_statement varchar2(1024);
v_result re_type;

BEGIN

for x in ( select username from dba_users)
LOOP

v_statement := 'select concat(lpad('' '', 2*level), granted_role) line1 from (select null grantee, username granted_role from dba_users where username = ''' || x.username || ''' union select grantee, granted_role from dba_role_privs union select grantee, privilege from dba_sys_privs ) start with grantee is null connect by grantee = prior granted_role';

execute immediate v_statement BULK COLLECT INTO v_result;

for indx in v_result.FIRST .. v_result.LAST
loop DBMS_OUTPUT.PUT_LINE(v_result(indx));

end loop; 

END LOOP;

END;

/

You get a formatted output like:

MYUSER1
    MYROLE_SESSION
      ALTER SESSION
      CREATE SESSION
    CONNECT
      CREATE SESSION
    MYROLE1
    MYROLE2
  MYUSER2
    CONNECT
      CREATE SESSION
    MYROLE1
    MYROLE3 

Particular thanks to Pete for seeing me past my quotes and array woes