Eduardokum\LaravelBoleto\Util::formatCnab PHP Method

    public static function formatCnab($tipo, $valor, $tamanho, $dec = 0, $sFill = '')
    {
        $string = $valor;
        if (in_array(strtoupper($tipo), array('9', 9, 'N', '9L', 'NL'))) {
            if (strtoupper($tipo) == '9L' || strtoupper($tipo) == 'NL') {
                $string = self::onlyNumbers($string);
            }
            $left = '';
            $sFill = 0;
            $type = 's';
            $string = $dec > 0 ? sprintf("%.{$dec}f", $string) : $string;
            $string = str_replace(array(',', '.'), '', $string);
        } else {
            if (in_array(strtoupper($tipo), array('A', 'X'))) {
                $left = '-';
                $type = 's';
                $string = strtoupper(self::normalizeChars($string));
            } else {
                if (in_array(strtoupper($tipo), array('AM', 'XM'))) {
                    $left = '-';
                    $type = 's';
                    $string = self::normalizeChars($string);
                } else {
                    if (strtoupper($tipo) == 'L') {
                        $left = '-';
                        $type = 's';
                        $string = self::normalizeChars($string);
                    } else {
                        if (strtoupper($tipo) == 'D') {
                            $tamanho = 6;
                            $left = '-';
                            $type = 's';
                            $string = $string->format('dmy');
                        } else {
                            throw new \Exception('Tipo inválido');
                        }
                    }
                }
            }
        }
        $string = substr($string, 0, $tamanho);
        return sprintf("%{$left}{$sFill}{$tamanho}{$type}", $string);
    }

 protected function trailer()
 {
     $this->iniciaTrailer();
     $this->add(1, 1, '9');
     $this->add(2, 394, '');
     $this->add(395, 400, Util::formatCnab('9', $this->getCount(), 6));
     return $this;
 }