code: func (c *Client) GetTokens(opts ...services.MarshalOption) ([]services.ProvisionToken, error) {
  	out, err := c.Get(c.Endpoint("tokens"), url.Values{})
  	if err != nil {
  		return nil, trace.Wrap(err)
  	}
  	var tokens []services.ProvisionTokenV1
  	if err := json.Unmarshal(out.Bytes(), &tokens); err != nil {
  		return nil, trace.Wrap(err)
  	}
  	return services.ProvisionTokensFromV1(tokens), nil
  }
docs: // GetTokens returns a list of active invitation tokens for nodes and users