code: func (c *Client) GetNamespaces() ([]services.Namespace, error) {
  	out, err := c.Get(c.Endpoint("namespaces"), url.Values{})
  	if err != nil {
  		return nil, trace.Wrap(err)
  	}
  	var re []services.Namespace
  	if err := utils.FastUnmarshal(out.Bytes(), &re); err != nil {
  		return nil, trace.Wrap(err)
  	}
  	return re, nil
  }
docs: // GetNamespaces returns a list of namespaces