assertUnescaped(e, '@');

    // Don't use plus for spaces
    assertEscaping(e, "%20", ' ');

    assertThat(e.escape("safe with spaces")).isEqualTo("safe%20with%20spaces");
    assertThat(e.escape("foo@bar.com")).isEqualTo("foo@bar.com");
  }

  private UrlEscaperTesting() {}

{* ../../docs_src/header_params/tutorial003_an_py310.py hl[9] *}

Si te comunicas con esa *path operation* enviando dos headers HTTP como:

```
X-Token: foo
X-Token: bar
```

El response sería como:

```JSON
{
    "X-Token values": [
        "bar",
        "foo"
    ]
}
```

## Recapitulación { #recap }

Declara headers con `Header`, usando el mismo patrón común que `Query`, `Path` y `Cookie`.

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(
    q: Annotated[str | None, Query(title="Query string", min_length=3)] = None,
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

                </div>
            </la:form>
        </section>
    </main>
    <jsp:include page="/WEB-INF/view/common/admin/footer.jsp"></jsp:include>
</div>
<jsp:include page="/WEB-INF/view/common/admin/foot.jsp"></jsp:include>
</body>

                </div>
            </la:form>
        </section>
    </main>
    <jsp:include page="/WEB-INF/view/common/admin/footer.jsp"></jsp:include>
</div>
<jsp:include page="/WEB-INF/view/common/admin/foot.jsp"></jsp:include>
</body>

                </div>
            </div>
        </section>
    </main>
    <jsp:include page="/WEB-INF/view/common/admin/footer.jsp"></jsp:include>
</div>
<jsp:include page="/WEB-INF/view/common/admin/foot.jsp"></jsp:include>
</body>

            if (arg.startsWith("\"")) {
                // if we're in the process of building up another arg, push it and start over.
                // this is for the case: "-Dfoo=bar "-Dfoo2=bar two" (note the first unterminated quote)
                if (currentArg != null) {
                    cleaned.add(currentArg.toString());
                }

                // start building an argument here.

          @Override
          protected String serviceName() {
            return "Foo";
          }
        };
    TimeoutException e =
        assertThrows(
            TimeoutException.class, () -> service.startAsync().awaitRunning(1, MILLISECONDS));
    assertThat(e)
        .hasMessageThat()
        .isEqualTo("Timed out waiting for Foo [STARTING] to reach the RUNNING state.");
  }

from fastapi import FastAPI, Response, status

app = FastAPI()

tasks = {"foo": "Listen to the Bar Fighters"}


@app.put("/get-or-create-task/{task_id}", status_code=200)
def get_or_create_task(task_id: str, response: Response):
    if task_id not in tasks:
        tasks[task_id] = "This didn't exist before"
        response.status_code = status.HTTP_201_CREATED

                </div>
            </div>
        </section>
    </main>
    <jsp:include page="/WEB-INF/view/common/admin/footer.jsp"></jsp:include>
</div>
<jsp:include page="/WEB-INF/view/common/admin/foot.jsp"></jsp:include>
</body>