code: func (s *TeamsService) ListUserTeams(ctx context.Context, opt *ListOptions) ([]*Team, *Response, error) {
  	u := "user/teams"
  	u, err := addOptions(u, opt)
  	if err != nil {
  		return nil, nil, err
  	}
  
  	req, err := s.client.NewRequest("GET", u, nil)
  	if err != nil {
  		return nil, nil, err
  	}
  
  	// TODO: remove custom Accept header when this API fully launches.
  	req.Header.Set("Accept", mediaTypeNestedTeamsPreview)
  
  	var teams []*Team
  	resp, err := s.client.Do(ctx, req, &teams)
  	if err != nil {
  		return nil, resp, err
  	}
  
  	return teams, resp, nil
  }
docs: // ListUserTeams lists a user's teams
  // GitHub API docs: https://developer.github.com/v3/teams/#list-user-teams