# Classes as Dependencies

Before diving deeper into the **Dependency Injection** system, let's upgrade the previous example.

## A `dict` from the previous example

In the previous example, we were returning a `dict` from our dependency ("dependable"):

//// tab | Python 3.10+

```Python hl_lines="9"
{!> ../../docs_src/dependencies/tutorial001_an_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="11"

import pytest
from dirty_equals import IsDict
from fastapi.testclient import TestClient

from ...utils import needs_py39


@pytest.fixture(name="client")
def get_client():
    from docs_src.bigger_applications.app_an_py39.main import app

    client = TestClient(app)
    return client


@needs_py39
def test_users_token_jessica(client: TestClient):
    response = client.get("/users?token=jessica")

import static java.nio.charset.StandardCharsets.UTF_8;

import java.util.Arrays;
import java.util.Random;
import junit.framework.TestCase;

/**
 * Unit tests for {@link Crc32c}. Known test values are from RFC 3720, Section B.4.
 *
 * @author Patrick Costello
 * @author Kurt Alfred Kluever
 */
public class Crc32cHashFunctionTest extends TestCase {
  public void testEmpty() {
    assertCrc(0, new byte[0]);
  }

	}

	reducedErr := reduceReadQuorumErrs(ctx, errs, objectOpIgnoredErrs, expectedRQuorum)
	if reducedErr != nil {
		return FileInfo{}, reducedErr
	}

	// List all the file commit ids from parts metadata.
	modTimes := listObjectModtimes(partsMetadata, errs)

	// Count all latest updated FileInfo values
	var count int
	var latestFileInfo FileInfo

import okhttp3.tls.HeldCertificate
import org.junit.jupiter.api.Test
import org.junit.jupiter.api.extension.RegisterExtension

/**
 * Tests for our hostname verifier. Most of these tests are from AOSP, which itself includes tests
 * from the Apache HTTP Client test suite.
 */
class HostnameVerifierTest {
  private val verifier = OkHostnameVerifier

  @RegisterExtension
  var platform = PlatformRule()

  @Test fun verify() {

from fastapi import Cookie, FastAPI

app = FastAPI()


@app.get("/items/")
async def read_items(ads_id: str | None = Cookie(default=None)):

to add trust for MinIO's own CA and for the CA of a Keycloak server, a Kubernetes secret can be created from the certificate files using `kubectl`: ``` kubectl -n minio create secret generic minio-trusted-certs --from-file=public.crt --from-file=keycloak.crt ``` If TLS is not enabled, you would need only the third party CA: ``` kubectl -n minio create secret generic minio-trusted-certs --from-file=keycloak.crt ``` The name of the generated secret can then be passed to Helm using a values file or...

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def root():

from fastapi import FastAPI

app = FastAPI(swagger_ui_parameters={"deepLinking": False})


@app.get("/users/{username}")
async def read_user(username: str):

from typing import Optional


def say_hi(name: Optional[str] = None):
    if name is not None:
        print(f"Hey {name}!")
    else: