// Assert
        assertNull(ex.getCause(), "Null cause should be preserved");
        assertNotNull(ex.toString(), "toString should be safe to call");
    }

    @ParameterizedTest
    @NullAndEmptySource
    @ValueSource(strings = { "oops", "multi word", "中文" })
    @DisplayName("Message+Cause constructor: preserves both values; no interactions with cause")

    private final Callable<T> delegate;

    WrappedCallable(Callable<T> delegate) {
      this.delegate = delegate;
    }

    @Override
    public T call() throws Exception {
      return delegate.call();
    }
  }

  private static final class WrappedRunnable implements Runnable {
    private final Runnable delegate;

    WrappedRunnable(Runnable delegate) {

       *
       * - In deleteDirectoryContents, the path argument may have no parent. Fortunately, all the
       *   *other* paths we process will be descendants of that. That leaves only the original path
       *   argument for us to consider. And the only place we call pathNotFound is from
       *   throwDeleteFailed, and the other place that we call throwDeleteFailed inside

    }
  }

  /**
   * Returns an unmodifiable <b>view</b> of the union of two sets. The returned set contains all
   * elements that are contained in either backing set. Iterating over the returned set iterates
   * first over all the elements of {@code set1}, then over each element of {@code set2}, in order,
   * that is not contained in {@code set1}.
   *

 * server's hostname is sent to the proxy.
 *
 * Prior to sending any CONNECT request OkHttp always calls the proxy authenticator so that it may
 * prepare preemptive authentication. OkHttp will call [authenticate] with a fake `HTTP/1.1 407
 * Proxy Authentication Required` response that has a `Proxy-Authenticate: OkHttp-Preemptive`

     */
    @Nonnull
    Optional<Source> locate(@Nonnull Path dir);

    /**
     * Parse the model obtained previously by a previous call to {@link #locate(Path)}.
     *
     * @param source the source to parse, never {@code null}
     * @param options possible parsing options, may be {@code null}
     * @return the parsed {@link Model}, never {@code null}

# 偵錯 { #debugging }

你可以在編輯器中連接偵錯器，例如 Visual Studio Code 或 PyCharm。

## 呼叫 `uvicorn` { #call-uvicorn }

在你的 FastAPI 應用程式中，直接匯入並執行 `uvicorn`：

{* ../../docs_src/debugging/tutorial001_py310.py hl[1,15] *}

### 關於 `__name__ == "__main__"` { #about-name-main }

`__name__ == "__main__"` 的主要目的是，當你的檔案以以下方式呼叫時，執行某些程式碼：

<div class="termy">

```console
$ python myapp.py
```

</div>

但當其他檔案匯入它時不會執行，例如：

```Python

// or a function call.
type PrimaryTerm struct {
	Value         *LitValue   `parser:"  @@"`
	JPathExpr     *JSONPath   `parser:"| @@"`
	ListExpr      *ListExpr   `parser:"| @@"`
	SubExpression *Expression `parser:"| \"(\" @@ \")\""`
	// Include function expressions here.
	FuncCall *FuncExpr `parser:"| @@"`
}

// FuncExpr represents a function call
type FuncExpr struct {

     * Provides a hint for how many values will be associated with each key newly added to the
     * builder after this call. This does not change semantics, but may improve performance if
     * {@code expectedValuesPerKey} is a good estimate.
     *
     * <p>This may be called more than once; each newly added key will use the most recent call to
     * {@link #expectedValuesPerKey} as its hint.
     *

//
// It dials one by one and returns first connected `net.Conn`.
// If it fails to dial all IPs from cache it returns first error. If no baseDialFunc
// is given, it sets default dial function.
//
// You can use returned dial function for `http.Transport.DialContext`.
//
// In this function, it uses functions from `rand` package. To make it really random,
// you MUST call `rand.Seed` and change the value from the default in your application