code: func GetParams(name string, r *http.Request) []string {
  	if params := r.Context().Value(ParamsKey); params != nil {
  		params := params.(Params)
  		if name != "*" {
  			name = ":" + name
  		}
  		if param := params[name]; param != nil {
  			switch param := param.(type) {
  			case []string:
  				return param
  			default:
  				return []string{param.(string)}
  			}
  		}
  	}
  	return []string{}
  }
docs: // GetParams returns param or params in a []string