You can use the same dependency *functions* you use normally.

### Dependency requirements { #dependency-requirements }

They can declare request requirements (like headers) or other sub-dependencies:

{* ../../docs_src/dependencies/tutorial006_an_py310.py hl[8,13] *}

### Raise exceptions { #raise-exceptions }

These dependencies can `raise` exceptions, the same as normal dependencies:

    }
  ]
}
```

because the path parameter `item_id` had a value of `"foo"`, which is not an `int`.

The same error would appear if you provided a `float` instead of an `int`, as in: [http://127.0.0.1:8000/items/4.2](http://127.0.0.1:8000/items/4.2)

/// check

So, with the same Python type declaration, **FastAPI** gives you data validation.

    // enclosed with same start
    assertEquals(range, range.span(Range.closed(4, 6)));

    // enclosed, interior
    assertEquals(range, range.span(Range.closed(5, 7)));

    // enclosed with same end
    assertEquals(range, range.span(Range.closed(6, 8)));

    // equal
    assertEquals(range, range.span(range));

    // enclosing with same start

   *       (<i>symmetric</i> property)
   *   <li>If {@code equivalent(x, y)} and {@code equivalent(y, z)} are both true, then {@code
   *       equivalent(x, z)} is also true (<i>transitive</i> property)
   * </ul>
   *
   * <p>Note that all calls to {@code equivalent(x, y)} are expected to return the same result as
   * long as neither {@code x} nor {@code y} is modified.

@GwtCompatible
@SuppressWarnings("rawtypes") // allow ungenerified Comparable types
public abstract class ContiguousSet<C extends Comparable> extends ImmutableSortedSet<C> {
  /**
   * Returns a {@code ContiguousSet} containing the same values in the given domain {@linkplain
   * Range#contains contained} by the range.
   *
   * @throws IllegalArgumentException if neither range nor the domain has a lower bound, or if
   *     neither has an upper bound

 *     their equivalent on the result of {@code Traverser.forTree(tree)} where {@code tree}
 *     implements {@code SuccessorsFunction}, which has a similar API as {@link #children} or can be
 *     the same lambda function as passed into {@link #using(Function)}.
 */
// This class is now only available externally for backwards compatibility; it should not be used

    entries.add(entry(null, v3()));

    resetContainer(getSubjectGenerator().create(entries.toArray()));
    assertTrue(
        "A Map should equal any other Map containing the same entries,"
            + " even if some keys are null.",
        getMap().equals(newHashMap(entries)));
  }

  @CollectionSize.Require(absent = CollectionSize.ZERO)
  public void testEquals_otherContainsNullKey() {

 * with the range (if any) that contains a specified key.
 *
 * <p>In contrast to {@link RangeSet}, no "coalescing" is done of {@linkplain
 * Range#isConnected(Range) connected} ranges, even if they are mapped to the same value.
 *
 * @author Louis Wasserman
 * @since 14.0
 */
@SuppressWarnings("rawtypes") // https://github.com/google/guava/issues/989
@DoNotMock("Use ImmutableRangeMap or TreeRangeMap")
@GwtIncompatible

If you have a big application, you might end up accumulating **several tags**, and you would want to make sure you always use the **same tag** for related *path operations*.

In these cases, it could make sense to store the tags in an `Enum`.

**FastAPI** supports that the same way as with plain strings:

{* ../../docs_src/path_operation_configuration/tutorial002b_py310.py hl[1,8:10,13,18] *}

@GwtCompatible
@SuppressWarnings("rawtypes") // allow ungenerified Comparable types
public abstract class ContiguousSet<C extends Comparable> extends ImmutableSortedSet<C> {
  /**
   * Returns a {@code ContiguousSet} containing the same values in the given domain {@linkplain
   * Range#contains contained} by the range.
   *
   * @throws IllegalArgumentException if neither range nor the domain has a lower bound, or if
   *     neither has an upper bound