# 進階 Python 型別 { #advanced-python-types }

以下是一些在使用 Python 型別時可能有用的額外想法。

## 使用 `Union` 或 `Optional` { #using-union-or-optional }

如果你的程式碼因某些原因無法使用 `|`，例如不是在型別註記中，而是在像 `response_model=` 之類的參數位置，那麼你可以用 `typing` 中的 `Union` 來取代豎線（`|`）。

例如，你可以宣告某個值可以是 `str` 或 `None`：

```python
from typing import Union


def say_hi(name: Union[str, None]):
        print(f"Hi {name}!")
```

在 `typing` 中也有用 `Optional` 宣告某個值可以是 `None` 的速記法。

    fi ;
    sleep 2 ; # 1 second intervals between attempts
    $MC_COMMAND ;
    STATUS=$? ;
  done ;
  set -e ; # reset `e` as active
  return 0
}

# checkUserExists ()
# Check if the user exists, by using the exit code of `mc admin user info`
checkUserExists() {
  CMD=$(${MC} admin user info myminio $(head -1 $MINIO_ACCESSKEY_SECRETKEY_TMP) > /dev/null 2>&1)
  return $?
}

# createUser ($policy)
createUser() {

kubectl get thirdpartyresource --all-namespaces -o yaml > tprs.yaml
kubectl delete -f tprs.yaml

After upgrading to 1.3.0, re-register the third party resource objects at the root scope (using a 1.3 server and client):

kubectl create -f tprs.yaml

#### kubectl

import java.util.Map;

import org.codelibs.fess.opensearch.config.allcommon.EsAbstractEntity;
import org.codelibs.fess.opensearch.config.bsentity.dbmeta.KeyMatchDbm;

/**
 * ${table.comment}
 * @author ESFlute (using FreeGen)
 */
public class BsKeyMatch extends EsAbstractEntity {

    // ===================================================================================

import org.dbflute.dbmeta.name.TableSqlName;
import org.dbflute.dbmeta.property.PropertyGateway;
import org.dbflute.dbway.DBDef;
import org.dbflute.util.DfTypeUtil;

/**
 * @author ESFlute (using FreeGen)
 */
public class ElevateWordToLabelDbm extends AbstractDBMeta {

    protected static final Class<?> suppressUnusedImportLocalDateTime = LocalDateTime.class;

import org.dbflute.cbean.ConditionQuery;
import org.opensearch.action.search.SearchRequestBuilder;
import org.opensearch.index.query.QueryBuilder;

/**
 * @author ESFlute (using FreeGen)
 */
public class BsWebConfigCB extends EsAbstractConditionBean {

    // ===================================================================================

     2. Build a Gradle distribution with this hash as a version + fixed timestamp -> dogfood-first
     3. Build a Gradle distribution using dogfood-first with this hash as a version + fixed timestamp different from the one above -> dogfood-second
     4. Use dogfood-second to run a Gradle build which runs tests.

     */

     * @throws IllegalArgumentException if the object cannot be processed
     */
    <T> T process(T object);

    /**
     * Process a model object using the first available processor implementation.
     *
     * <p>This method discovers processor implementations via ServiceLoader and
     * uses the first one found. If no implementations are available, the object

query_or_cookie_extractor(["query_or_cookie_extractor"])

read_query["/items/"]

query_extractor --> query_or_cookie_extractor --> read_query
```

## Dieselbe Abhängigkeit mehrmals verwenden { #using-the-same-dependency-multiple-times }

import static java.util.Objects.requireNonNull;

/**
 * Inliner POM transformer. The goal of this transformer is to fix Maven 3 issue about emitting (installing, deploying)
 * unusable POMs when using CI Friendly Versions.
 *
 * @since TBD
 */
@Singleton
@Named
class PomInlinerTransformer extends TransformerSupport {
    private final Interpolator interpolator;

    @Inject