code: public function getFrom()
      {
          if ($this->from === null) {
              if ($this->getStartType() == BinlogParser::START_TYPE_DATE) {
                  $temp_date = $this->getPairStorage()->get(self::LAST_SYNC_DATE_PARAM);
  
                  if ($temp_date === null) {
                      $this->generateLastSyncNotSetError(self::LAST_SYNC_DATE_PARAM);
                  } else {
                      $this->from = new DateTime($temp_date);
                  }
              } elseif ($this->getStartType() == BinlogParser::START_TYPE_POSITION) {
                  $this->from = $this->getPairStorage()->get(self::LAST_SYNC_POSITION_PARAM);
  
                  if ($this->from === null) {
                      $this->generateLastSyncNotSetError(self::LAST_SYNC_POSITION_PARAM);
                  }
              }
          }
  
          return $this->from;
      }
docs: @return \DateTime|int
  
  @throws \InvalidArgumentException