}
    },
    NEW {
      @Override
      long copy(Readable from, Appendable to) throws IOException {
        return CharStreams.copy(from, to);
      }
    };

    abstract long copy(Readable from, Appendable to) throws IOException;
  }

  enum TargetSupplier {
    STRING_WRITER {
      @Override
      Appendable get(int sz) {
        return new StringWriter(sz);
      }
    },
    STRING_BUILDER {

/**
 * Writer that places all output on an {@link Appendable} target. If the target is {@link Flushable}
 * or {@link Closeable}, flush()es and close()s will also be delegated to the target.
 *
 * @author Alan Green
 * @author Sebastian Kanthak
 * @since 1.0
 */
@J2ktIncompatible
@GwtIncompatible
final class AppendableWriter extends Writer {
  private final Appendable target;
  private boolean closed;

  /**

import org.apache.maven.api.annotations.Nonnull;

/**
 * Message builder that supports configurable styling.
 *
 * @since 4.0.0
 * @see MessageBuilderFactory
 */
public interface MessageBuilder extends Appendable {

    /**
     * Append message content in trace style.
     * By default, bold magenta
     *
     * @param message the message to append
     * @return the current builder
     */
    @Nonnull

Diese können so **tief** verschachtelt sein, wie nötig.

**FastAPI** kümmert sich darum, sie aufzulösen.

## Erste Abhängigkeit, „Dependable“ { #first-dependency-dependable }

Sie könnten eine erste Abhängigkeit („Dependable“) wie folgt erstellen:

{* ../../docs_src/dependencies/tutorial005_an_py310.py hl[8:9] *}

package ioutil

import (
	"io"
	"os"
)

// AppendFile - appends the file "src" to the file "dst"
func AppendFile(dst string, src string, osync bool) error {
	flags := os.O_WRONLY | os.O_APPEND | os.O_CREATE
	if osync {
		flags |= os.O_SYNC
	}
	appendFile, err := os.OpenFile(dst, flags, 0o666)
	if err != nil {
		return err
	}
	defer appendFile.Close()

	srcFile, err := os.Open(src)
	if err != nil {

You can create dependencies that have **sub-dependencies**.

They can be as **deep** as you need them to be.

**FastAPI** will take care of solving them.

## First dependency "dependable" { #first-dependency-dependable }

You could create a first dependency ("dependable") like:

{* ../../docs_src/dependencies/tutorial005_an_py310.py hl[8:9] *}

It declares an optional query parameter `q` as a `str`, and then it just returns it.

	if err != nil {
		t.Fatal(err)
	}

	err = fs.AppendFile(context.Background(), "voldir", "/file", []byte("hello"))
	if err != nil {
		t.Fatal(err)
	}

	// Try to create a file that includes a file in its path components.
	// In *nix, this returns syscall.ENOTDIR while in windows we receive the following error.
	err = fs.AppendFile(context.Background(), "voldir", "/file/obj1", []byte("hello"))

이것을 해결하는 일은 **FastAPI**가 알아서 처리합니다.

## 첫 번째 의존성 "dependable" { #first-dependency-dependable }

다음과 같이 첫 번째 의존성("dependable")을 만들 수 있습니다:

{* ../../docs_src/dependencies/tutorial005_an_py310.py hl[8:9] *}

이 의존성은 선택적 쿼리 파라미터 `q`를 `str`로 선언하고, 그대로 반환합니다.

매우 단순한 예시(그다지 유용하진 않음)이지만, 하위 의존성이 어떻게 동작하는지에 집중하는 데 도움이 됩니다.

## 두 번째 의존성 "dependable"과 "dependant" { #second-dependency-dependable-and-dependant }

它們可以按你的需要，層級任意加深。

**FastAPI** 會負責解析它們。

## 第一個相依項 "dependable" { #first-dependency-dependable }

你可以建立第一個相依項（"dependable"）如下：

{* ../../docs_src/dependencies/tutorial005_an_py310.py hl[8:9] *}

它宣告了一個可選的查詢參數 `q`（型別為 `str`），然後直接回傳它。

這很簡單（不太實用），但有助於我們專注於子相依如何運作。

## 第二個相依，同時是 "dependable" 也是 "dependant" { #second-dependency-dependable-and-dependant }

接著你可以建立另一個相依函式（"dependable"），同時它也宣告了自己的相依（因此它同時也是 "dependant"）：

## Друга залежність, «dependable» і «dependant» { #second-dependency-dependable-and-dependant }

Далі ви можете створити іншу функцію залежності («dependable»), яка водночас оголошує власну залежність (тож вона також є «dependant»):

{* ../../docs_src/dependencies/tutorial005_an_py310.py hl[13] *}

Зосередьмося на оголошених параметрах: