code: public function getTypes($region = null)
      {
          if (null === $region) {
              $ret = [];
              foreach ($this->matrix as $types) {
                  $ret = array_merge($ret, $types);
              }
  
              return array_values(array_unique($ret));
          }
  
          return $this->matrix[$region];
      }
docs: Returns the available types for a specified region.
  If not specified, returns all types configured.
  
  @param string $region
  
  @return array