How to get values from beego AppConfig and render it in HTML template?

I want to get value of a key defined in beego's app.conf and render in html pages. As per documentation on http://ift.tt/1s0k4F5 I can get value of AppConfig by using config function in templates. However there is no example in documentation.

Get the value of AppConfig. . configType must be String, Bool, Int, Int64, Float, or DIY

After trying many ways I came to this:

<div></div>

But I am always getting error:

<config>: wrong number of args for config: want 3 got 0

What is the correct way to use config template function?