How to call getCollection() from a doc inside the collection?

getCollection(upOne)

<% for document in @getCollection('./blogs').toJSON(): %>
	<li typeof="sioc:Page" about="<%= document.url %>" class="<%= 'active'  if @document.url is document.url %>">
		<a href="<%= document.url %>" property="dc:title"><%= document.title %></a>
	</li>
<% end %>

The above causes the following error:

error: An error occured:
TypeError: Cannot call method 'toJSON' of undefined

One workaround is to have the posts folder lower than the getCollection('posts') or in another documents/posts folder.