code: public function debit($account, $amount, \DateTime $date)
      {
          $data = [
              $this->date,
              $account,
              $this->identity,
              null,
              $amount,
              $this->number,
              $date->format('Y-m-d'),
          ];
  
          if (false === fputcsv($this->handle, $data, ';', '"')) {
              throw new RuntimeException("Failed to write line.");
          }
      }
docs: Writes the debit line.
  
  @param string    $account
  @param string    $amount
  @param \DateTime $date