code: func Uaa(clientId, clientSecret, username, password, accessToken, refreshToken string, usingClientCrendentials bool) Builder {
  	return func(config Config) (Strategy, error) {
  		httpClient := config.Client()
  		authUrl, err := config.AuthURL()
  
  		if err != nil {
  			return nil, err
  		}
  
  		uaaClient := uaa.Client{
  			AuthURL: authUrl,
  			Client:  httpClient,
  		}
  
  		oauth := &OAuthStrategy{
  			Username:                username,
  			Password:                password,
  			ClientId:                clientId,
  			ClientSecret:            clientSecret,
  			ApiClient:               httpClient,
  			OAuthClient:             &uaaClient,
  			ClientCredentialRefresh: usingClientCrendentials,
  		}
  
  		oauth.SetTokens(accessToken, refreshToken)
  
  		return oauth, nil
  	}
  }
docs: // Uaa builds an OauthStrategy for a UAA using existing tokens