}
            // Simulate some encoding activity on the buffer
            dst.enc_ndr_long(123);
        }

        @Override
        public void decode(NdrBuffer src) throws NdrException {
            if (throwOnDecode) {
                throw new NdrException("Failed to decode");
            }
            // Simulate some decoding activity on the buffer
            src.dec_ndr_long();

# Advanced Python Types { #advanced-python-types }

Here are some additional ideas that might be useful when working with Python types.

## Using `Union` or `Optional` { #using-union-or-optional }

If your code for some reason can't use `|`, for example if it's not in a type annotation but in something like `response_model=`, instead of using the vertical bar (`|`) you can use `Union` from `typing`.

```

...this would work:

```JSON
{
    "item_id": "foo-item",
    "needy": "sooooneedy"
}
```

And of course, you can define some parameters as required, some as having a default value, and some entirely optional:

{* ../../docs_src/query_params/tutorial006_py310.py hl[8] *}

In this case, there are 3 query parameters:

* `needy`, a required `str`.

					toSend = append(toSend, payload...)
					select {
					case <-ctx.Done():
						return nil
					case out <- toSend:
					}
				}
				return nil
			},

			Subroute:    "some-subroute",
			OutCapacity: 1, // Only one message buffered.
			InCapacity:  0,
		}))
		errFatal(err)
	}
	const payloadSize = 512
	rng := rand.New(rand.NewSource(time.Now().UnixNano()))

    should not use them for communication between trusted and untrusted code.

6.  For the mainline flavor, we test the libraries using OpenJDK 8, 11, and 17
    on Linux, with some additional testing on newer JDKs and on Windows. Some
    features, especially in `com.google.common.io`, may not work correctly in
    non-Linux environments. For the Android flavor, our unit tests also run on
    API level 23 (Marshmallow).

        )

        failureConditions {
            // JavaExecDebugIntegrationTest.debug session fails without debugger might cause JVM crash
            // Some soak tests produce OOM exceptions
            // There are also random worker crashes for some tests.
            // We have test-retry to handle the crash in tests
            javaCrash = false
        }
    })

fun getTestTaskName(

        assertDoesNotThrow(() -> bufferManager.cleanup());

        // After cleanup, all regions should be released (but the count may not match exactly
        // if some regions were pooled rather than immediately released)
        assertTrue(bufferManager.getTotalReleased() > 0, "Some regions should be released during cleanup");
        assertEquals(allocatedBeforeCleanup, bufferManager.getTotalReleased(),

It should be a `list` of `Depends()`:

{* ../../docs_src/dependencies/tutorial006_an_py310.py hl[19] *}

These dependencies will be executed/solved the same way as normal dependencies. But their value (if they return any) won't be passed to your *path operation function*.

/// tip

Some editors check for unused function parameters, and show them as errors.

			// directory" error message. Handle this specifically
			// here.
			return errFileAccessDenied
		}
	}
	return err
}

// Reliably retries os.RemoveAll if for some reason os.RemoveAll returns
// syscall.ENOTEMPTY (children has files).
func reliableRemoveAll(dirPath string) (err error) {
	i := 0
	for {
		// Removes all the directories and files.

Let's imagine that we want to have a dependency that checks if the query parameter `q` contains some fixed content.

But we want to be able to parameterize that fixed content.

## A "callable" instance { #a-callable-instance }

In Python there's a way to make an instance of a class a "callable".