<div class="screenshot">
<img src="/img/tutorial/query-param-models/image01.png">
</div>

## Forbid Extra Query Parameters { #forbid-extra-query-parameters }

In some special use cases (probably not very common), you might want to **restrict** the query parameters that you want to receive.

You can use Pydantic's model configuration to `forbid` any `extra` fields:

{* ../../docs_src/query_param_models/tutorial002_an_py310.py hl[10] *}

    this.iterator = iterator;
  }

  @Override
  public Iterator<E> iterator() {
    if (iterator == null) {
      // TODO: throw something else? Do we worry that people's code and tests
      // might be relying on this particular type of exception?
      throw new IllegalStateException();
    }
    try {
      return iterator;
    } finally {
      iterator = null;
    }
  }

                    + " because they threaten the stability of your build.");
            LOGGER.warn("");
            LOGGER.warn("For this reason, future Maven versions might no"
                    + " longer support building such malformed projects.");
            LOGGER.warn("");
        }

        return projects;
    }

So, if you have an object `something` (that might _not_ be a function) and you can "call" it (execute it) like:

```Python
something()
```

or

```Python
something(some_argument, some_keyword_argument="foo")
```

then it is a "callable".

## Classes as dependencies { #classes-as-dependencies_1 }

You might notice that to create an instance of a Python class, you use that same syntax.

            UpgradeContext context = createMockContext();
            UpgradeResult result = strategy.doApply(context, pomMap);

            assertTrue(result.success(), "Plugin upgrade should succeed");
            // POM might still be marked as modified due to other plugin management additions
        }

        @Test
        @DisplayName("should upgrade plugin in pluginManagement")

			return false
		}
	}
	return true
}

// It would be nice if the error messages always began with
// the standard file:line: prefix,
// but that's not where we are today.
// It might be at the beginning but it might be in the middle of the printed instruction.
var fileLineRE = regexp.MustCompile(`(?:^|\()(testdata[/\\][\da-z]+\.s:\d+)(?:$|\)|:)`)

// Same as in test/run.go
var (

# JSON Compatible Encoder { #json-compatible-encoder }

There are some cases where you might need to convert a data type (like a Pydantic model) to something compatible with JSON (like a `dict`, `list`, etc).

For example, if you need to store it in a database.

For that, **FastAPI** provides a `jsonable_encoder()` function.

## Using the `jsonable_encoder` { #using-the-jsonable-encoder }

 * to half-width and to convert any characters to lowercase, ensuring consistency in the output.
 * </p>
 *
 * <p>
 * Example:
 * For the input "キャ", the converter might return a list containing "kya".
 * For the input "ジュ", the converter might return a list containing "zyu", "ju", and "jyu".
 * </p>
 *
 */
public class KatakanaToAlphabetConverter implements ReadingConverter {

certificate.

The trusted roots don't need to be the same for client and server when using client authentication.
Clients might rely on the platform certificates and servers might use a private
organization-specific certificate authority.

By default `HeldCertificate` instances expire after 24 hours. Use `duration()` to adjust.

Note that the go_darwin_$GOARCH_exec wrapper uninstalls any existing app identified by
the bundle id before installing a new app. If the uninstalled app is the last app by
the developer identity, the device might also remove the permission to run apps from
that developer, and the exec wrapper will fail to install the new app. To avoid that,
install another app with the same developer identity but with a different bundle id.