code: func (s *Session) Flashes(vars ...string) []interface{} {
  	var flashes []interface{}
  	key := flashesKey
  	if len(vars) > 0 {
  		key = vars[0]
  	}
  	if v, ok := s.Values[key]; ok {
  		// Drop the flashes and return it.
  		delete(s.Values, key)
  		flashes = v.([]interface{})
  	}
  	return flashes
  }
docs: // Flashes returns a slice of flash messages from the session.
  //
  // A single variadic argument is accepted, and it is optional: it defines
  // the flash key. If not defined "_flash" is used by default.