include template function with arguments

The documentation for the include template function states:

      Includes the contents of another file and renders in-place.
      Optionally can pass key-value pairs as arguments to be accessed by the included file.

     {{include "path/to/file.html"}}  // no arguments
     {{include "path/to/file.html" "arg1" 2 "value 3"}}  // with arguments

How does one access these arguments? 