Rails error_messages helper

This is a very common piece of code

&开发者_如何学JAVAlt;% form_for :blah... do |f| %>
<%= f.error_messages %>
First name: <%= f.text_field :first_name %><br />
....
<% end %>

error_messages is a helper method but I am having a hard time finding the documentation for it, why is that?

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I found them here: error_messages have same params as error_messages_for.

In Rails 3 however, error_messages and error_messages_for have been deprecated and have been moved out to a plugin.