public function test_cant_discharge_from_in_twice()
{
$billet = factory(Billet::class)->create();
$dischargeDate = $billet->dischargeFrom();
$this->assertInstanceOf(Carbon::class, $billet->discharge_date);
$this->assertFalse($billet->dischargeFrom($dischargeDate->copy()->addSecond(5)));
}