private function toGrpcValue(array $property)
    {
        $type = array_keys($property)[0];
        $val = $property[$type];
        if ($val === null) {
            $val = NullValue::NULL_VALUE;
        }

        if ($type === 'timestampValue') {
            $val = $this->formatTimestampForApi($val);
        }

        if ($type === 'geoPointValue') {
            $val = $this->arrayFilterRemoveNull($val);
        }

        return [$type, $val];
    }