{!../../docs_src/bigger_applications/app/main.py!}
```

and it will work correctly, together with all the other *path operations* added with `app.include_router()`.

/// info | Very Technical Details

**Note**: this is a very technical detail that you probably can **just skip**.

---

The `APIRouter`s are not "mounted", they are not isolated from the rest of the application.

///

//// tab | `venv`

To create a virtual environment, you can use the `venv` module that comes with Python.

<div class="termy">

```console
$ python -m venv .venv
```

</div>

/// details | What that command means

* `python`: use the program called `python`
* `-m`: call a module as a script, we'll tell it which module next
* `venv`: use the module called `venv` that normally comes installed with Python

        NtlmPasswordAuthenticator startAuth = new NtlmPasswordAuthenticator("domain", "user", new String(diffAtStart));
        NtlmPasswordAuthenticator middleAuth = new NtlmPasswordAuthenticator("domain", "user", new String(diffAtMiddle));
        NtlmPasswordAuthenticator endAuth = new NtlmPasswordAuthenticator("domain", "user", new String(diffAtEnd));

        try {

/**
 * Default implementation of the IntervalController.
 * This class provides a default way to manage delays between crawler operations.
 * It allows setting delays before processing, after processing, when no URLs are in the queue,
 * and when waiting for new URLs.
 * The delays are configurable via constructor parameters.
 *
 */
public class DefaultIntervalController extends AbstractIntervalController {

        super(message, cause);
    }

    /**
     * Constructs a new CrawlerSystemException with the specified detail message.
     *
     * @param message the detail message. The detail message is saved for later retrieval by the {@link #getMessage()} method.
     */
    public CrawlerSystemException(final String message) {
        super(message);
    }

    /**

public class GsaConfigException extends FessSystemException {

    private static final long serialVersionUID = 1L;

    /**
     * Constructs a new GSA configuration exception with the specified detail message and cause.
     *
     * @param message the detail message describing the configuration error
     * @param cause the cause of the exception
     */
    public GsaConfigException(final String message, final Throwable cause) {

    @Test
    @DisplayName("Should handle case sensitivity in domain and workstation")
    void testCaseSensitivity() {
        // Given
        String domain = "TestDomain";
        String workstation = "TestWorkstation";

        // When
        Type1Message type1 = new Type1Message(mockContext, 0, domain, workstation);

        // Then
        assertEquals(domain, type1.getSuppliedDomain());

    private Throwable rootCause;

    /**
     * Constructs a new TransportException with no detail message.
     */
    public TransportException() {
    }

    /**
     * Constructs a new TransportException with the specified detail message.
     *
     * @param msg the detail message
     */
    public TransportException(final String msg) {
        super(msg);
    }

    /**

     *
     * @param crudMode the CRUD mode
     * @param id the key match ID
     * @return HTML response for the details page
     */
    @Execute
    @Secured({ ROLE, ROLE + VIEW })
    public HtmlResponse details(final int crudMode, final String id) {
        verifyCrudMode(crudMode, CrudMode.DETAILS);
        saveToken();
        final List<Map<String, Object>> docList = new ArrayList<>();

        assertEquals(domain, type1Message.getSuppliedDomain());
    }

    @Test
    void testInitSecContext_state2_type3Message() throws Exception {
        // Test the second step (processing Type 2 and creating Type 3 message)
        when(mockAuth.getDomain()).thenReturn(domain);
        when(mockAuth.getUsername()).thenReturn(username);