//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package cmd

// isDirEmpty - returns true if there is no error and no object and prefix inside this directory
func isDirEmpty(dirname string, _ bool) bool {
	entries, err := readDirN(dirname, 1)
	if err != nil {
		return false
	}
	return len(entries) == 0

{!> ../../docs_src/query_params_str_validations/tutorial009.py!}
```

////

## Deprecating parameters

Now let's say you don't like this parameter anymore.

You have to leave it there a while because there are clients using it, but you want the docs to clearly show it as <abbr title="obsolete, recommended not to use it">deprecated</abbr>.

Then pass the parameter `deprecated=True` to `Query`:

 *
 * @author Charles Fry
 * @since 11.0
 */
@GwtCompatible
@FunctionalInterface
@ElementTypesAreNonnullByDefault
public interface Weigher<K, V> {

  /**
   * Returns the weight of a cache entry. There is no unit for entry weights; rather they are simply
   * relative to each other.
   *
   * @return the weight of the entry; must be non-negative
   */
  int weigh(K key, V value);

 *
 * @author Charles Fry
 * @since 11.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public interface Weigher<K, V> {

  /**
   * Returns the weight of a cache entry. There is no unit for entry weights; rather they are simply
   * relative to each other.
   *
   * @return the weight of the entry; must be non-negative
   */
  int weigh(K key, V value);

@ElementTypesAreNonnullByDefault
public interface RangeMap<K extends Comparable, V> {
  /*
   * TODO(cpovirk): These docs sometimes say "map" and sometimes say "range map." Pick one, or at
   * least decide on a policy for when to use which.
   */

  /**
   * Returns the value associated with the specified key, or {@code null} if there is no such value.
   *
   * <p>Specifically, if any range in this range map contains the specified key, the value

## Overriding dependencies during testing

There are some scenarios where you might want to override a dependency during testing.

You don't want the original dependency to run (nor any of the sub-dependencies it might have).

Instead, you want to provide a different dependency that will be used only during tests (possibly only some specific tests), and will provide a value that can be used where the value of the original dependency was used.

from fastapi import FastAPI, Header, HTTPException
from pydantic import BaseModel

fake_secret_token = "coneofsilence"

fake_db = {
    "foo": {"id": "foo", "title": "Foo", "description": "There goes my hero"},
    "bar": {"id": "bar", "title": "Bar", "description": "The bartenders"},
}

app = FastAPI()


class Item(BaseModel):
    id: str
    title: str
    description: str | None = None

import org.junit.jupiter.api.Test;

import static org.junit.jupiter.api.Assertions.assertEquals;

/**
 * A test which demonstrates maven's recursive inheritance where
 * a distinct value is taken from each parent contributing to
 * the final model of the project being assembled. There is no
 * overriding going on amongst the models being used in this test:
 * each model in the lineage is providing a value that is not present

    protected String wildcard;
    protected int attributes;

/* This filter can be considerably more efficient than other file filters
 * as the specifed wildcard and attributes are passed to the server for
 * filtering there (although attributes are largely ignored by servers
 * they are filtered locally by the default accept method).
 */
    public DosFileFilter( String wildcard, int attributes ) {
        this.wildcard = wildcard;

# 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`

Let's imagine that you have a database `fake_db` that only receives JSON compatible data.