[PrestaShopException]

Property Cart->id_currency is empty
at line 837 in file classes/ObjectModel.php

831. 
832. 			$message = $this->validateField($field, $this->$field);
833. 			if ($message !== true)
834. 			{
835. 				if ($die)
836. 					throw new PrestaShopException($message);
837. 				return $error_return ? $message : false;
838. 			}
839. 		}
840. 
841. 		return true;