whoan

class DFS {
  enum Method {
    PreOrder, InOrder, PostOrder
  } method;

  enum Direction {
    LeftToRight, RightToLeft
  } direction;

  template <typename TreeNode>

whoan

// suppose `brothers` has a user_id foreign key

class User extends Model
{
    public function brothers() {
        return $this->hasMany('App\Brother');
    }
}

// bad way