}
		netLimitSem <- struct{}{}
		hasToken = true
	}

	checker := new(netTokenChecker)
	runtime.SetFinalizer(checker, (*netTokenChecker).panicUnreleased)

	return func() {
		if checker.released {
			panic("internal error: net token released twice")
		}
		checker.released = true
		if hasToken {
			<-netLimitSem
		}
		runtime.SetFinalizer(checker, nil)
	}, nil
}

var (
	netLimitOnce sync.Once

		}

		fmt.Fprint(os.Stderr, msg)
	}
	os.Exit(code)
}

// CheckErr prints a user friendly error to STDERR and exits with a non-zero
// exit code. Unrecognized errors will be printed with an "error: " prefix.
//
// This method is generic to the command in use and may be used by non-Kubectl
// commands.
func CheckErr(err error) {
	checkErr(err, fatal)
}

```Python hl_lines="16"
{!../../../docs_src/dependencies/tutorial011.py!}
```

这样就可以**参数化**依赖项，它包含 `checker.fixed_content` 的属性 - `"bar"`。

## 把实例作为依赖项

然后，不要再在 `Depends(checker)` 中使用 `Depends(FixedContentQueryChecker)`， 而是要使用 `checker`，因为依赖项是类实例 - `checker`，不是类。

处理依赖项时，**FastAPI** 以如下方式调用 `checker`：

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

……并用*路径操作函数*的参数 `fixed_content_included` 返回依赖项的值：

```Python hl_lines="20"

## 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")
```

			return errors.NewBadRequest(bodyText)
		case resp.StatusCode == http.StatusNotFound:
			return errors.NewGenericServerResponse(resp.StatusCode, "", checker.QualifiedResource, checker.Name, bodyText, 0, false)
		}
		return errors.NewGenericServerResponse(resp.StatusCode, "", checker.QualifiedResource, checker.Name, bodyText, 0, false)
	}
	return nil
}

          "version": {
            "requires": "${jsr305.version}"
          }
        },
        {
          "group": "org.checkerframework",
          "module": "checker-qual",
          "version": {
            "requires": "${checker.version}"
          }
        },
        {
          "group": "com.google.errorprone",
          "module": "error_prone_annotations",
          "version": {

          <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" />

    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)]):

// An error_ represents a type-checking error.
// A new error_ is created with Checker.newError.
// To report an error_, call error_.report.
type error_ struct {
	check *Checker
	desc  []errorDesc
	code  Code
	soft  bool // TODO(gri) eventually determine this from an error code
}

// newError returns a new error_ with the given error code.
func (check *Checker) newError(code Code) *error_ {
	if code == 0 {

## Die Instanz als Abhängigkeit verwenden

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
checker(q="somequery")