*       typically because the type forbids nullable type arguments: For example, {@code
 *       ImmutableList.get} returns {@code E}, but that value is never {@code null}. (Accordingly,
 *       {@code ImmutableList} is declared to forbid {@code ImmutableList<@Nullable String>}.)
 *   <li>methods whose return type is a type variable but which can return {@code null} regardless
 *       of the type argument supplied by the user of the class: For example, {@code

 *       typically because the type forbids nullable type arguments: For example, {@code
 *       ImmutableList.get} returns {@code E}, but that value is never {@code null}. (Accordingly,
 *       {@code ImmutableList} is declared to forbid {@code ImmutableList<@Nullable String>}.)
 *   <li>methods whose return type is a type variable but which can return {@code null} regardless
 *       of the type argument supplied by the user of the class: For example, {@code

 *       typically because the type forbids nullable type arguments: For example, {@code
 *       ImmutableList.get} returns {@code E}, but that value is never {@code null}. (Accordingly,
 *       {@code ImmutableList} is declared to forbid {@code ImmutableList<@Nullable String>}.)
 *   <li>methods whose return type is a type variable but which can return {@code null} regardless
 *       of the type argument supplied by the user of the class: For example, {@code

 *       typically because the type forbids nullable type arguments: For example, {@code
 *       ImmutableList.get} returns {@code E}, but that value is never {@code null}. (Accordingly,
 *       {@code ImmutableList} is declared to forbid {@code ImmutableList<@Nullable String>}.)
 *   <li>methods whose return type is a type variable but which can return {@code null} regardless
 *       of the type argument supplied by the user of the class: For example, {@code

* `Field(index=True)` tells SQLModel that it should create a **SQL index** for this column, that would allow faster lookups in the database when reading data filtered by this column.

    SQLModel will know that something declared as `str` will be a SQL column of type `TEXT` (or `VARCHAR`, depending on the database).

### Create an Engine { #create-an-engine }

{* ../../docs_src/response_headers/tutorial002_py310.py hl[1, 7:8] *}

And then you can return any object you need, as you normally would (a `dict`, a database model, etc).

And if you declared a `response_model`, it will still be used to filter and convert the object you returned.

          return Indexed.this;
        }

        // redeclare to help optimizers with b/310253115
        @SuppressWarnings("RedundantOverride")
        @Override
        @J2ktIncompatible
        @GwtIncompatible
                Object writeReplace() {
          return super.writeReplace();
        }
      };
    }

    // redeclare to help optimizers with b/310253115

</div>

## Forbid Extra Form Fields { #forbid-extra-form-fields }

In some special use cases (probably not very common), you might want to **restrict** the form fields to only those declared in the Pydantic model. And **forbid** any **extra** fields.

/// note

This is supported since FastAPI version `0.114.0`. 🤓

///

You can use Pydantic's model configuration to `forbid` any `extra` fields:

   *
   * (That would also have ensured that its cause was always an Error, rather than possibly another
   * kind of Throwable that was later passed to initCause. Then we could have declared the override
   * `public final Error getCause()`.)
   */

  /**
   * Creates a new instance with {@code null} as its detail message and no cause.
   *

   */
  @Deprecated
  @DoNotCall("Always throws UnsupportedOperationException")
  public static <E> ImmutableSortedSet.Builder<E> builder() {
    throw new UnsupportedOperationException();
  }

  // redeclare to help optimizers with b/310253115
  @SuppressWarnings("RedundantOverride")
  @J2ktIncompatible // serialization
  @Override
  @GwtIncompatible // serialization
  Object writeReplace() {