entries().asSequence()
                .filter { it.name.isClassFilePath }
                .map { kotlinSourceNameOf(it.name) }
        }

    private
    fun sourceNamesFromDir(dir: File): Sequence<String> =
        dir.walkTopDown()
            .filter { it.name.isClassFilePath }
            .map { kotlinSourceNameOf(normaliseFileSeparators(it.relativeTo(dir).path)) }

    private

        final Iterator<String> it = new MultiIterator<String>(list1.iterator(), list2.iterator());

        assertThat(it.hasNext(), is(true));
        assertThat(it.next(), is("Foo"));

        assertThat(it.hasNext(), is(true));
        assertThat(it.next(), is("Bar"));

        assertThat(it.hasNext(), is(true));
        assertThat(it.next(), is("Baz"));

        assertThat(it.hasNext(), is(not(true)));
    }

    ```

Let's focus on the parameters declared:

* Even though this function is a dependency ("dependable") itself, it also declares another dependency (it "depends" on something else).
    * It depends on the `query_extractor`, and assigns the value returned by it to the parameter `q`.
* It also declares an optional `last_query` cookie, as a `str`.

        final ClassLoaderIterator it = new ClassLoaderIterator(cl3);
        assertThat(it.hasNext(), is(true));
        assertThat(it.next(), is(sameInstance(cl3)));

        assertThat(it.hasNext(), is(true));
        assertThat(it.next(), is(sameInstance(cl2)));

        assertThat(it.hasNext(), is(true));
        assertThat(it.next(), is(sameInstance(cl1)));

        assertThat(it.hasNext(), is(not(true)));
    }

        By asking questions in a structured way (following this) it will be much easier to help you.

        And there's a high chance that you will find the solution along the way and you won't even have to submit it and wait for an answer. 😎

    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)));

To create the callback *path operation* use the same `APIRouter` you created above.

It should look just like a normal FastAPI *path operation*:

* It should probably have a declaration of the body it should receive, e.g. `body: InvoiceEvent`.
* And it could also have a declaration of the response it should return, e.g. `response_model=InvoiceEventReceived`.

```Python hl_lines="16-18  21-22  28-32"

    That's because it is using the same name as in the OpenAPI spec. So that if you need to investigate more about any of these security schemes you can just copy and paste it to find more information about it.

The `oauth2_scheme` variable is an instance of `OAuth2PasswordBearer`, but it is also a "callable".

It could be called as:

```Python
oauth2_scheme(some, parameters)
```

The result of calling it is something that can be encoded with the Python standard <a href="https://docs.python.org/3/library/json.html#json.dumps" class="external-link" target="_blank">`json.dumps()`</a>.

It doesn't return a large `str` containing the data in JSON format (as a string). It returns a Python standard data structure (e.g. a `dict`) with values and sub-values that are all compatible with JSON.

!!! note

                "maven-it-plugin",
                "0.1",
                "compile",
                "jar",
                null,
                new DefaultArtifactHandler("ignore"));
        PluginDescriptor descriptor = new PluginDescriptor();
        descriptor.setGroupId("org.apache.maven.its.plugins");
        descriptor.setArtifactId("maven-it-plugin");
        descriptor.setVersion("0.1");