></DD
></DL
></DIV
><P>
  </P
><P
>   If <TT
CLASS="LITERAL"
>TD["when"]</TT
> is <TT
CLASS="LITERAL"
>BEFORE</TT
> or
   <TT
CLASS="LITERAL"
>INSTEAD OF</TT
> and
   <TT
CLASS="LITERAL"
>TD["level"]</TT
> is <TT
CLASS="LITERAL"
>ROW</TT
>, you can
   return <TT
CLASS="LITERAL"
>None</TT
> or <TT
CLASS="LITERAL"
>"OK"</TT
> from the
   Python function to indicate the row is unmodified,
   <TT
CLASS="LITERAL"
>"SKIP"</TT
> to abort the event, or if <TT
CLASS="LITERAL"
>TD["event"]</TT
>
   is <TT
CLASS="COMM