public function trade($symbol, $quantity, $side, $type = 'MARKET', $price = false)
    {
        $data = [
            'symbol'   => $symbol,
            'side'     => $side,
            'type'     => $type,
            'quantity' => $quantity
        ];
        if($price !== false)
        {
            $data['price'] = $price;
        }

        $b = $this->privateRequest('v3/order', $data, 'POST');
    
        return $b;
    }