ProductVariation::canPurchase PHP Method

    public function canPurchase($member = null, $quantity = 1)
    {
        $allowpurchase = false;
        if ($product = $this->Product()) {
            $allowpurchase = ($this->sellingPrice() > 0 || Product::config()->allow_zero_price) && $product->AllowPurchase;
        }
        $permissions = $this->extend('canPurchase', $member, $quantity);
        $permissions[] = $allowpurchase;
        return min($permissions);
    }