code: func (c *PDNSAPIClient) PartitionZones(zones []pgo.Zone) (filteredZones []pgo.Zone, residualZones []pgo.Zone) {
  	if c.domainFilter.IsConfigured() {
  		for _, zone := range zones {
  			if c.domainFilter.Match(zone.Name) {
  				filteredZones = append(filteredZones, zone)
  			} else {
  				residualZones = append(residualZones, zone)
  			}
  		}
  	} else {
  		filteredZones = zones
  	}
  	return filteredZones, residualZones
  }
docs: // PartitionZones : Method returns a slice of zones that adhere to the domain filter and a slice of ones that does not adhere to the filter