code: public static function formattedTime($DateTime_str = 'now', $timestamp_format = null, $timezone = null) {
          if (!$timestamp_format) {
              $timestamp_format = static::$timestamp_format;
          }
  
          if (!$timezone) {
              $timezone = static::$timezone;
          }
  
          $tz = new \DateTimeZone($timezone);
          $time = new \DateTime($DateTime_str, $tz);
  
          if ($time->getTimeZone()->getName() !== $tz->getName()) {
              $time->setTimeZone($tz);
          }
  
          return $time->format($timestamp_format);
      }
docs: Returns a date/time string with the specified timestamp format
  
  $time = Date::formatted_time('5 minutes ago');
  
  @link    http://www.php.net/manual/\DateTime.construct
  @param   string $\DateTime_str       \DateTime string
  @param   string $timestamp_format timestamp format
  @param   string $timezone timezone identifier
  @return  string