Then you declare your data model as a class that inherits from `BaseModel`.

Use standard Python types for all the attributes:

{* ../../docs_src/body/tutorial001_py310.py hl[5:9] *}


The same as when declaring query parameters, when a model attribute has a default value, it is not required. Otherwise, it is required. Use `None` to make it just optional.

///

```Python hl_lines="7  13"
{!> ../../docs_src/request_files/tutorial001_03.py!}
```

////

## Multiple File Uploads

It's possible to upload several files at the same time.

They would be associated to the same "form field" sent using "form data".

To use that, declare a list of `bytes` or `UploadFile`:

//// tab | Python 3.9+

```Python hl_lines="10  15"

/**
 * A bimap (or "bidirectional map") is a map that preserves the uniqueness of its values as well as
 * that of its keys. This constraint enables bimaps to support an "inverse view", which is another
 * bimap containing the same entries as this bimap but with reversed keys and values.
 *
 * <h3>Implementations</h3>
 *
 * <ul>
 *   <li>{@link ImmutableBiMap}
 *   <li>{@link HashBiMap}
 *   <li>{@link EnumBiMap}

  }

  /**
   * Returns an immutable bimap containing the given entries. The returned bimap iterates over
   * entries in the same order as the original iterable.
   *
   * @throws IllegalArgumentException if two keys have the same value or two values have the same
   *     key
   * @throws NullPointerException if any key, value, or entry is null
   * @since 19.0
   */

  /**
   * Creates an {@code ImmutableMap} backed by a JDK HashMap. Used when probable hash flooding is
   * detected. This implementation may replace the entries in entryArray with its own entry objects
   * (though they will have the same key/value contents), and will take ownership of entryArray.
   */
  static <K, V> ImmutableMap<K, V> create(
      int n, @Nullable Entry<K, V>[] entryArray, boolean throwIfDuplicateKeys) {

};

// An abstract operation describes an operation by its type, name, and
// attributes. It can be "executed" by the context with some input tensors.
// It is allowed to reusing the same abstract operation for multiple execution
// on a given context, with the same or different input tensors.
class TracingOperation : public AbstractOperation {
 protected:
  explicit TracingOperation(AbstractOperationKind kind)
      : AbstractOperation(kind) {}

They are just a convenience, they hold the same number, but that way you can use the editor's autocomplete to find them:

<img src="/img/tutorial/response-status-code/image02.png">

/// note | "Technical Details"

You could also use `from starlette import status`.

   *   <li>{@code proxy.toString()} delegates to {@link AbstractInvocationHandler#toString}
   *   <li>{@code proxy.equals(argument)} returns true if:
   *       <ul>
   *         <li>{@code proxy} and {@code argument} are of the same type
   *         <li>and {@link AbstractInvocationHandler#equals} returns true for the {@link
   *             InvocationHandler} of {@code argument}
   *       </ul>

import junit.framework.TestCase;

/**
 * Test cases for {@code EventBus} that must not be in the same package.
 *
 * @author Louis Wasserman
 */
public class OutsideEventBusTest extends TestCase {

  /*
   * If you do this test from common.eventbus.EventBusTest, it doesn't actually test the behavior.
   * That is, even if exactly the same method works from inside the common.eventbus package tests,
   * it can fail here.
   */

  public void testConstructor2NPE() {
    double[] a = null;
    assertThrows(NullPointerException.class, () -> new AtomicDoubleArray(a));
  }

  /** constructor with array is of same size and has all elements */
  public void testConstructor2() {
    AtomicDoubleArray aa = new AtomicDoubleArray(VALUES);
    assertEquals(VALUES.length, aa.length());
    for (int i = 0; i < VALUES.length; i++) {