protected function convertPropertyValueToSimpleType($value)
    {
        if ($value instanceof \DateTime) {
            // CMIS expects a timestamp in milliseconds
            $value = $value->getTimestamp() * 1000;
        } elseif (is_bool($value)) {
			// Booleans must be represented in string form since request will fail if cast to integer
			$value = $value ? 'true' : 'false';
		}

        return $value;
    }