code: func (c *Catalog) Datacenters() ([]string, error) {
  	r := c.c.newRequest("GET", "/v1/catalog/datacenters")
  	_, resp, err := requireOK(c.c.doRequest(r))
  	if err != nil {
  		return nil, err
  	}
  	defer resp.Body.Close()
  
  	var out []string
  	if err := decodeBody(resp, &out); err != nil {
  		return nil, err
  	}
  	return out, nil
  }
docs: // Datacenters is used to query for all the known datacenters