code: func (ts *TemplateSet) Execute(w io.Writer, name string, obj interface{}) error {
  	tpl, ok := ts.tpls[name]
  	if !ok {
  		// attempt to load and parse the template
  		buf, err := ts.l(name)
  		if err != nil {
  			return err
  		}
  
  		// parse template
  		tpl, err = template.New(name).Funcs(ts.funcs).Parse(string(buf))
  		if err != nil {
  			return err
  		}
  	}
  
  	return tpl.Execute(w, obj)
  }
docs: // Execute executes a specified template in the template set using the supplied
  // obj as its parameters and writing the output to w.