<%= yield %>
<%= f.fields_for association, associate, :builder => f.class do |nested_f| %>
<%= nested_f.hidden_field :_destroy, :class => :destroy_nested_one, :value => local_assigns[:has_zero] %>
<%= content_tag :div, :class => :nested_one, :style => ('display:none' if local_assigns[:has_zero]) do %>
<%= render :partial => nested_partial,
:object => nested_f.object,
:as => nested_f.object.class.name.underscore.to_sym,
:locals => {:f => nested_f} %>
<% end %>
<% end %>