ruby-on-rails-3 - 设计中的参数错误

Question

谁能告诉我为什么在 Devise/sessions#new 中运行 devise ArgumentError 时出现以下错误

显示

C:/Rails/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/devise-1.1.rc0/app/views/devise/sessions/new.html.erb where line #3 raised:

wrong number of arguments (3 for 2)
Extracted source (around line #3):

1: <h2>Sign in</h2>
2: 
3: <%= form_for(resource_name, resource, :url => session_path(resource_name)) do |f| %>
4:   <p><%= f.label :email %></p>
5:   <p><%= f.text_field :email %></p>
6: