Currently working on nested forms with the following railscast <http://railscasts.com/episodes/196-nested-model-form-revised>

I have an Opportunity model,

```
class Opportunity < ActiveRecord::Base
    has_many :headings
    accepts_nested_attributes_for :headings
end

```

a Heading model

```
class Heading < ActiveRecord::Base
    belongs_to :opportunity
    has_many :subheadings
    accepts_nested_attributes_for :subheadings
end

```

and a Subheading model

```
class Subheading < ActiveRecord::Base
    belongs_to :heading
end

```

Right now I am just working on the view for the new action for the Opportunity model.

```
<h1>Add an opportunity</h1>
<%= form_for(@opportunity, :html => {:role => 'form'}) do |f| %>
    <%= f.fields_for :headings do |builder| %>
        <%= render 'heading_fields', f: builder %>
    <% end %>
    <%= link_to_add_fields "Add heading", f, :headings %>
    <%= f.submit %>
<% end %>

```

And the \_heading\_fields.html.erb partial:

```
<fieldset>
    <%= f.label :title, "Heading" %>
    <%= f.text_field :title %>
    <%= f.hidden_field :_destroy %>
    <%= link_to "Remove section", '#', class: "remove_fields" %>
    <%= link_to_add_fields "Add section", f, :subheadings %>
</fieldset>

```

And finally the link\_to\_add\_fields method in the application helper:

```
def link_to_add_fields(name, f, association)
    new_object = f.object.send(association).klass.new
    id = new_object.object_id
    fields = f.fields_for(association, new_object, child_index: id) do |builder|
        render(association.to_s.singularize + "_fields", f: builder)
    end
    link_to(name, '#', class: "add_fields", data: {id: id, fields: fields.gsub("\n", "")})
end

```

Now I am receiving the following error for the render call in the link\_to\_add\_fields function:

```
syntax error, unexpected tIDENTIFIER, expecting keyword_end

```

It seems to have something to do with the underscore in the name of the partial being rendered in the link\_to\_add\_fields method as it goes away when the underscore is not present.

Greatly appreciate any help at solving this headache!