code: func (p *Plugin) Open(fn *function.Function) error {
  	if !strings.HasPrefix(fn.Runtime, "python") {
  		return nil
  	}
  
  	// Support "python" for backwards compat.
  	if fn.Runtime == "python" {
  		fn.Runtime = "python2.7"
  	}
  
  	if fn.Handler == "" {
  		fn.Handler = "main.handle"
  	}
  
  	return nil
  }
docs: // Open adds python defaults.