///

## OpenAPI and API docs { #openapi-and-api-docs }

If you return additional status codes and responses directly, they won't be included in the OpenAPI schema (the API docs), because FastAPI doesn't have a way to know beforehand what you are going to return.

DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

{* ../../docs_src/request_forms_and_files/tutorial001_an_py39.py hl[3] *}

## Define `File` and `Form` parameters { #define-file-and-form-parameters }

Create file and form parameters the same way you would for `Body` or `Query`:

{* ../../docs_src/request_forms_and_files/tutorial001_an_py39.py hl[10:12] *}

The files and form fields will be uploaded as form data and you will receive the files and form fields.

* **Asynchronous Code**
* **`async` and `await`**
* **Coroutines**

## Asynchronous Code { #asynchronous-code }

Asynchronous code just means that the language 💬 has a way to tell the computer / program 🤖 that at some point in the code, it 🤖 will have to wait for *something else* to finish somewhere else. Let's say that *something else* is called "slow-file" 📝.

 * unloading an OSGi bundle.
 *
 * <p>{@code com.google.common.base.FinalizableReferenceQueue} loads this class in its own class
 * loader. That way, this class doesn't prevent the main class loader from getting garbage
 * collected, and this class can detect when the main class loader has been garbage collected and
 * stop itself.
 */

  public final boolean trySetAccessible() {
    // We can't call accessibleObject.trySetAccessible since that was added in Java 9 and this code
    // should work on Java 8. So we emulate it this way.
    try {
      accessibleObject.setAccessible(true);
      return true;
    } catch (Exception e) { // sneaky checked exception
      return false;
    }
  }

            "msg": "Extra inputs are not permitted",
            "input": "plumbus",
        }
    ]
}
```

## Disable Convert Underscores { #disable-convert-underscores }

The same way as with regular header parameters, when you have underscore characters in the parameter names, they are **automatically converted to hyphens**.

  static final ReverseNaturalOrdering INSTANCE = new ReverseNaturalOrdering();

  @Override
  @SuppressWarnings("unchecked") // TODO(kevinb): the right way to explain this??
  public int compare(Comparable<?> left, Comparable<?> right) {
    checkNotNull(left); // right null is caught later
    if (left == right) {
      return 0;
    }

/**
 * Implementation detail for the internal structure of {@link Range} instances. Represents a unique
 * way of "cutting" a "number line" (actually of instances of type {@code C}, not necessarily
 * "numbers") into two sections; this can be done below a certain value, above a certain value,
 * below all values or above all values. With this object defined in this way, an interval can
 * always be represented by a pair of {@code Cut} instances.
 *