code: function( input, chunk, context ){
      // return given input if there is no dust reference to resolve
      var output = input;
      // dust compiles a string to function, if there are references
      if( typeof input === "function"){
        if( ( typeof input.isReference !== "undefined" ) && ( input.isReference === true ) ){ // just a plain function, not a dust `body` function
          output = input();
        } else {
          output = '';
          chunk.tap(function(data){
            output += data;
            return '';
          }).render(input, context).untap();
          if( output === '' ){
            output = false;
          }
        }
      }
      return output;
    }
docs: Utility helping to resolve dust references in the given chunk