multipart form_tag

I'm new to ruby, working on the book from Christian Hellsten & Jarkko
Laine writen for RoR 1, so I had to adapt for RoR 2.
I got the error :
undefined local variable or method `multipart' for
#<#<Class:0xb714d388>:0xb714d360>
Code :
1: <h1>Editing book</h1>
2:
3: <% form_tag( {:action => 'update', :id => @book}, multipart => true )
do %>
4: <%= render :partial => 'form' %>
5: <%= submit_tag 'Edit' %>
6: <% end %>
I tried several variants, some module missing ??
Thanks for any help.

just a typo, multipart should be :multipart

Thorsten Mueller wrote:

just a typo, multipart should be :multipart

3: <% form_tag( {:action => 'update', :id => @book}, :multipart => true )
do %>

Thanks a lot, more obvious, more difficult to see sometimes!