code: public function getLastTimestamp($tags)
      {
          // extract the TimePoint identification from the provided item, and find existing range
          $range = $this->getRange($tags);
          $length = count($range);
          $last = false;
  
          if ($length) {
              $last = $range[$length - 1]->getTimestamp();
          }
  
          return $last;
      }
docs: Gets the last timestamp of the range for the provided tags
  @param string|array $tags
  @return bool|float $timestamp Returns the last timestamp of the range or false if none