code: func (client *Client) GetTags(source string) (TagMap, error) {
  	var out reqGetTags
  	uri := "/v1/tags/hosts"
  	if source != "" {
  		uri += "?source=" + source
  	}
  	if err := client.doJsonRequest("GET", uri, nil, &out); err != nil {
  		return nil, err
  	}
  	return *out.Tags, nil
  }
docs: // GetTags returns a map of tags.