code: func (api *API) DeleteFilter(zoneID, filterID string) error {
  	if filterID == "" {
  		return errors.Errorf("filter ID cannot be empty")
  	}
  
  	uri := fmt.Sprintf("/zones/%s/filters/%s", zoneID, filterID)
  
  	_, err := api.makeRequest("DELETE", uri, nil)
  	if err != nil {
  		return errors.Wrap(err, errMakeRequestError)
  	}
  
  	return nil
  }
docs: // DeleteFilter deletes a single filter.
  //
  // API reference: https://developers.cloudflare.com/firewall/api/cf-filters/delete/#delete-a-single-filter