code: func CallByID(client *messagebird.Client, id string) (*Call, error) {
  	var resp struct {
  		Data []Call `json:"data"`
  	}
  	if err := client.Request(&resp, http.MethodGet, apiRoot+"/calls/"+id, nil); err != nil {
  		return nil, err
  	}
  	return &resp.Data[0], nil
  }
docs: // CallByID fetches a call by it's ID.
  //
  // An error is returned if no such call flow exists or is accessible.