});

        ShareEnumIterator it = new ShareEnumIterator(parent, entries.iterator(), filter);

        // Returns only accepted resources
        assertTrue(it.hasNext());
        assertEquals("keep1/", it.next().getName());
        assertTrue(it.hasNext());
        assertEquals("keep2/", it.next().getName());
        assertFalse(it.hasNext());

        // Verify filter called once per entry

It used custom types in its declarations instead of standard Python types, but it was still a huge step forward.

It also was one of the first frameworks to generate a custom schema declaring the whole API in JSON.

It was not based on a standard like OpenAPI and JSON Schema. So it wouldn't be straightforward to integrate it with other tools, like Swagger UI. But again, it was a very innovative idea.

    public void test() throws Exception {
        final ClassIterator it = new ClassIterator(Integer.class);
        assertThat(it.hasNext(), is(true));
        assertThat(it.next(), is(sameClass(Integer.class)));

        assertThat(it.hasNext(), is(true));
        assertThat(it.next(), is(sameClass(Number.class)));

        assertThat(it.hasNext(), is(true));
        assertThat(it.next(), is(sameClass(Object.class)));

        // Act
        TestIterator it = TestIterator.create(tree, parent, wildcard, null, attrs, initial, pages);

        // Assert
        assertSame(tree, it.getTreeHandle(), "tree handle should be same instance returned by acquire");
        assertEquals(attrs, it.getSearchAttributes());
        assertEquals(wildcard, it.getWildcard());
        assertSame(parent, it.getParent());
        verify(tree, times(1)).acquire();

                            os to (testProject to performanceTestDuration)
                        }
                }
            }
        return pairs
            .groupBy({ it.first }, { it.second })
            .mapValues { entry -> entry.value.groupBy({ it.first }, { it.second }) }
    }

    private fun readPerformanceTestConfigurations(performanceTestsCiJson: File): List<PerformanceTestConfiguration> {

Let's use the tools provided by **FastAPI** to handle security.

## How it looks { #how-it-looks }

Let's first just use the code and see how it works, and then we'll come back to understand what's happening.

## Create `main.py` { #create-main-py }

Copy the example in a file `main.py`:

{* ../../docs_src/security/tutorial001_an_py39.py *}

## Run it { #run-it }

/// info

* It takes each **request** that comes to your application.
* It can then do something to that **request** or run any needed code.
* Then it passes the **request** to be processed by the rest of the application (by some *path operation*).

freetls.fastly.net
frei.no
freight.aero
frenchkiss.jp
fresenius
friuli-v-giulia.it
friuli-ve-giulia.it
friuli-vegiulia.it
friuli-venezia-giulia.it
friuli-veneziagiulia.it
friuli-vgiulia.it
friuliv-giulia.it
friulive-giulia.it
friulivegiulia.it
friulivenezia-giulia.it
friuliveneziagiulia.it
friulivgiulia.it
frl
frogans
frogn.no
froland.no
from-ak.com
from-al.com

It might be useful, for example, to return custom headers or cookies.

## Return a `Response` { #return-a-response }

In fact, you can return any `Response` or any sub-class of it.

/// tip

`JSONResponse` itself is a sub-class of `Response`.

///

And when you return a `Response`, **FastAPI** will pass it directly.

```JSON
{
    "name": "Foo",
    "price": 45.2
}
```

## Declare it as a parameter { #declare-it-as-a-parameter }

To add it to your *path operation*, declare it the same way you declared path and query parameters:

{* ../../docs_src/body/tutorial001_py310.py hl[16] *}

...and declare its type as the model you created, `Item`.