```JSON
{"item_id":3}
```

/// check

Notice that the value your function received (and returned) is `3`, as a Python `int`, not a string `"3"`.

So, with that type declaration, **FastAPI** gives you automatic request <abbr title="converting the string that comes from an HTTP request into Python data">"parsing"</abbr>.

///

## Data validation { #data-validation }

   * explicit {@code @NullableDecl} annotation (see <a
   * href="https://github.com/google/guava/issues/1819">#1819</a>).
   *
   * <p>It is not necessary to consider visibility, return type, or type parameter declarations. The
   * declaration of a method with the same name and formal parameters as {@link Object#equals} that
   * is not public and boolean-returning, or that declares any type parameters, would be rejected at
   * compile-time.
   */

```Python
my_list: list[str]
```

In versions of Python before 3.9, it would be:

```Python
from typing import List

my_list: List[str]
```

That's all standard Python syntax for type declarations.

Use that same standard syntax for model attributes with internal types.

So, in our example, we can make `tags` be specifically a "list of strings":

/**
 * Tests for {@link RequestParam} covering enum mechanics and edge cases.
 */
@ExtendWith(MockitoExtension.class)
public class RequestParamTest {

    // Happy path: values() returns all constants in declaration order
    @Test
    @DisplayName("values() returns all declared constants in order")
    void valuesContainsAllInOrder() {
        RequestParam[] values = RequestParam.values();

     * non-reified type or has bounds, {@code forDependants} is used to do further resolution, which
     * doesn't try to resolve any type variable on generic declarations that are already being
     * resolved.
     *
     * <p>Should only be called and overridden by {@link #resolve(TypeVariable)}.
     */
    Type resolveInternal(TypeVariable<?> var, TypeTable forDependants) {

/**
 * Tester of subtyping relationships between two types.
 *
 * <p>Tests should inherit from this class, and declare subtyping relationship with public methods
 * annotated by {@link TestSubtype}.
 *
 * <p>These declaration methods rely on Java static type checking to make sure what we want to
 * assert as subtypes are really subtypes according to javac. For example:
 *
 * {@snippet :
 * class MySubtypeTests extends SubtypeTester {

    }
  }

  /**
   * Returns a new {@link TypeVariable} that belongs to {@code declaration} with {@code name} and
   * {@code bounds}.
   */
  static <D extends GenericDeclaration> TypeVariable<D> newArtificialTypeVariable(
      D declaration, String name, Type... bounds) {
    return newTypeVariableImpl(
        declaration, name, (bounds.length == 0) ? new Type[] {Object.class} : bounds);
  }

Now that we have seen how to use `Path` and `Query`, let's see more advanced uses of request body declarations.

## Mix `Path`, `Query` and body parameters { #mix-path-query-and-body-parameters }

First, of course, you can mix `Path`, `Query` and request body parameter declarations freely and **FastAPI** will know what to do.

And you can also declare body parameters as optional, by setting the default to `None`:

  }

  @Override
  public @Nullable Object[] toArray() {
    return standardToArray();
  }

  @Override
  @SuppressWarnings("nullness") // b/192354773 in our checker affects toArray declarations
  public <T extends @Nullable Object> T[] toArray(T[] array) {
    return standardToArray(array);
  }

  @Override
  public String toString() {
    return entrySet().toString();
  }

    }
  }

  /**
   * Returns a new {@link TypeVariable} that belongs to {@code declaration} with {@code name} and
   * {@code bounds}.
   */
  static <D extends GenericDeclaration> TypeVariable<D> newArtificialTypeVariable(
      D declaration, String name, Type... bounds) {
    return newTypeVariableImpl(
        declaration, name, (bounds.length == 0) ? new Type[] {Object.class} : bounds);
  }