## Dispatch

For synchronous calls, you bring your own thread and are responsible for managing how many simultaneous requests you make. Too many simultaneous connections wastes resources; too few harms latency.

    from docs_src.dependencies.tutorial008d import InternalError

    with pytest.raises(InternalError) as exc_info:
        client.get("/items/portal-gun")
    assert (
        exc_info.value.args[0] == "The portal gun is too dangerous to be owned by Rick"
    )


def test_internal_server_error():
    from docs_src.dependencies.tutorial008d import app

    client = TestClient(app, raise_server_exceptions=False)

* for **input** the `description` will **not be required**
* for **output** it will be **required** (and possibly `None`, or in JSON terms, `null`)

### Model for Output in Docs

You can check the output model in the docs too, **both** `name` and `description` are marked as **required** with a **red asterisk**:

<div class="screenshot">
<img src="/img/tutorial/separate-openapi-schemas/image03.png">
</div>

### Model for Input and Output in Docs

public class DefaultRootLocator implements RootLocator {

    public boolean isRootDirectory(Path dir) {
        if (Files.isDirectory(dir.resolve(".mvn"))) {
            return true;
        }
        // we're too early to use the modelProcessor ...
        Path pom = dir.resolve("pom.xml");
        try (InputStream is = Files.newInputStream(pom)) {
            XMLStreamReader parser = XMLInputFactory.newFactory().createXMLStreamReader(is);

			for k := range exp {
				if exp[k] != got[k] {
					t.Fatalf("interval %s: Expected %d values but got %d values\n", k, exp[k], got[k])
				}
			}
			// what is absent in exp is absent in got too
			for k := range got {
				if _, ok := exp[k]; !ok && got[k] > 0 {
					t.Fatalf("Unexpected interval: %s has value %d\n", k, got[k])
				}
			}
		})
	}
}

@app.get("/items/{item_id}")
def get_item(item_id: str, username: Annotated[str, Depends(get_username)]):
    if item_id == "portal-gun":
        raise InternalError(
            f"The portal gun is too dangerous to be owned by {username}"
        )
    if item_id != "plumbus":
        raise HTTPException(
            status_code=404, detail="Item not found, there's only a plumbus here"
        )

    "I",  # isort
    "B",  # flake8-bugbear
    "C4",  # flake8-comprehensions
    "UP",  # pyupgrade
]
ignore = [
    "E501",  # line too long, handled by black
    "B008",  # do not perform function calls in argument defaults
    "C901",  # too complex
    "W191",  # indentation contains tabs
]

[tool.ruff.lint.per-file-ignores]
"__init__.py" = ["F401"]

            .suppressing(parentBuilder.getSuppressedTests())
            .suppressing(SetCreationTester.class.getMethods())
            // BiMap.entrySet() duplicate-handling behavior is too confusing for SetCreationTester
            .withSetUp(parentBuilder.getSetUp())
            .withTearDown(parentBuilder.getTearDown())
            .createTestSuite());
    /*

  pos: Int,
  limit: Int,
): ByteArray? {
  val address = ByteArray(16)
  var b = 0
  var compress = -1
  var groupOffset = -1

  var i = pos
  while (i < limit) {
    if (b == address.size) return null // Too many groups.

    // Read a delimiter.
    if (i + 2 <= limit && input.startsWith("::", startIndex = i)) {
      // Compression "::" delimiter, which is anywhere in the input, including its prefix.

            "+1.+2.+3.4",
            "1.2.3.4e0",
            "6:5:4:3:2:1:0", // too few parts
            "::7:6:5:4:3:2:1:0", // too many parts
            "7:6:5:4:3:2:1:0::", // too many parts
            "9:8:7:6:5:4:3::2:1", // too many parts
            "0:1:2:3::4:5:6:7", // :: must remove at least one 0.
            "3ffe:0:0:0:0:0:0:0:1", // too many parts (9 instead of 8)
            "3ffe::10000", // hextet exceeds 16 bits