## Utilize a instância como dependência { #use-the-instance-as-a-dependency }

Então, nós podemos utilizar este `checker` em um `Depends(checker)`, no lugar de `Depends(FixedContentQueryChecker)`, porque a dependência é a instância, `checker`, e não a própria classe.

E quando a dependência for resolvida, o **FastAPI** chamará este `checker` como:

```Python
checker(q="somequery")

    def __call__(self, q: str = ""):
        if q:
            return self.fixed_content in q
        return False


checker = FixedContentQueryChecker("bar")


@app.get("/query-checker/")
async def read_query_check(fixed_content_included: Annotated[bool, Depends(checker)]):

          <item index="10" class="java.lang.String" itemvalue="org.checkerframework.checker.nullness.compatqual.NullableDecl" />
          <item index="11" class="java.lang.String" itemvalue="org.checkerframework.checker.nullness.compatqual.NullableType" />
          <item index="12" class="java.lang.String" itemvalue="org.checkerframework.checker.nullness.qual.Nullable" />

	if idxName != "idx_public_table_name" {
		t.Errorf("invalid index name generated, got %v", idxName)
	}

	chkName := ns.CheckerName("public.table", "name")
	if chkName != "chk_public_table_name" {
		t.Errorf("invalid checker name generated, got %v", chkName)
	}

	joinTable := ns.JoinTableName("user_languages")
	if joinTable != "public.user_languages" {
		t.Errorf("invalid join table generated, got %v", joinTable)
	}

## Die Instanz als Abhängigkeit verwenden { #use-the-instance-as-a-dependency }

Dann könnten wir diesen `checker` in einem `Depends(checker)` anstelle von `Depends(FixedContentQueryChecker)` verwenden, da die Abhängigkeit die Instanz `checker` und nicht die Klasse selbst ist.

Und beim Auflösen der Abhängigkeit ruft **FastAPI** diesen `checker` wie folgt auf:

```Python

    public T get() {
      // A 2-field variant of Double Checked Locking.
      if (!initialized) {
        synchronized (lock) {
          if (!initialized) {
            T t = delegate.get();
            value = t;
            initialized = true;
            return t;
          }
        }
      }
      // This is safe because we checked `initialized`.
      return uncheckedCastNullableTToT(value);
    }

        return id;
    }

    /**
     * Set a filter value based on checked state (add if checked, remove if unchecked)
     */
    function setFilter(array, value, checked) {
        var index = array.indexOf(value);
        if (checked && index === -1) {
            array.push(value);
        } else if (!checked && index !== -1) {
            array.splice(index, 1);
        }
    }

    /**

## Use the instance as a dependency { #use-the-instance-as-a-dependency }

Then, we could use this `checker` in a `Depends(checker)`, instead of `Depends(FixedContentQueryChecker)`, because the dependency is the instance, `checker`, not the class itself.

And when solving the dependency, **FastAPI** will call this `checker` like:

```Python
checker(q="somequery")
```

{
  "upstream": "elastic/elasticsearch",
  "targetBranchChoices": [
    { "name": "master", "checked": true },
    { "name": "7.x", "checked": true },
    "7.15",
    "7.14",
    "6.8"
  ],
  "targetPRLabels": ["backport"],
  "branchLabelMapping": {
    "^v8.0.0$": "master",
    "^v7.16.0$": "7.x",
    "^v(\\d+).(\\d+).\\d+$": "$1.$2"
  }

이렇게 하면 `checker.fixed_content` 속성에 `"bar"`라는 값을 담아 의존성을 "매개변수화"할 수 있습니다.

## 인스턴스를 의존성으로 사용하기 { #use-the-instance-as-a-dependency }

그런 다음, 클래스 자체가 아닌 인스턴스 `checker`가 의존성이 되므로, `Depends(FixedContentQueryChecker)` 대신 `Depends(checker)`에서 이 `checker` 인스턴스를 사용할 수 있습니다.

의존성을 해결할 때 **FastAPI**는 이 `checker`를 다음과 같이 호출합니다:

```Python
checker(q="somequery")
```