belongsTo(Invoice::class); } public function payment() { return $this->belongsTo(Payment::class); } /* ATTRIBUTES */ /** * If our amount is negative, and invoice_id is null, then this is a reversal. * * @param $value * @return float */ public function getAllocAmtAttribute($value): float { return (is_null($this->invoice_id) && $value < 0) ? -$value : $value; } }