cases section below.

To access a struct, union, or enum type directly, prefix it with
struct_, union_, or enum_, as in C.struct_stat. The size of any C type
T is available as C.sizeof_T, as in C.sizeof_struct_stat. These
special prefixes means that there is no way to directly reference a C
identifier that starts with "struct_", "union_", "enum_", or
"sizeof_", such as a function named "struct_function".

///

{* ../../docs_src/extra_models/tutorial003_py310.py hl[1,14:15,18:20,33] *}

### `Union` в Python 3.10 { #union-in-python-3-10 }

  }

  /**
   * Returns a new range set consisting of the union of this range set and {@code other}.
   *
   * <p>This is essentially the same as {@code TreeRangeSet.create(this).addAll(other)} except it
   * returns an {@code ImmutableRangeSet}.
   *
   * @since 21.0
   */
  public ImmutableRangeSet<C> union(RangeSet<C> other) {
    return unionOf(Iterables.concat(asRanges(), other.asRanges()));
  }

  /**

  }

  /**
   * Returns a new range set consisting of the union of this range set and {@code other}.
   *
   * <p>This is essentially the same as {@code TreeRangeSet.create(this).addAll(other)} except it
   * returns an {@code ImmutableRangeSet}.
   *
   * @since 21.0
   */
  public ImmutableRangeSet<C> union(RangeSet<C> other) {
    return unionOf(Iterables.concat(asRanges(), other.asRanges()));
  }

  /**

    assertMinSize(union(emptySet(), emptySet()), 0);
    assertMinSize(union(setSize(2), setSize(3)), 3);
    assertMinSize(union(setSize(3), setSize(2)), 3);
    assertMinSize(union(setSizeRange(10, 20), setSizeRange(11, 12)), 11);
    assertMinSize(union(setSizeRange(11, 12), setSizeRange(10, 20)), 11);
  }

  public void testUnion_maxSize() {
    assertMaxSize(union(emptySet(), emptySet()), 0);

또한, 유효한 Pydantic 타입이 아닌 타입이 하나 이상 포함된 여러 타입 간의 <dfn title="여러 타입 간의 union은 '이 타입들 중 아무거나'를 의미합니다.">union</dfn>이 있는 경우에도 동일합니다. 예를 들어, 아래는 실패합니다 💥:

{* ../../docs_src/response_model/tutorial003_04_py310.py hl[8] *}

...이는 타입 어노테이션이 Pydantic 타입이 아니고, 단일 `Response` 클래스/서브클래스도 아니며, `Response`와 `dict` 간 union(둘 중 아무거나)이기 때문에 실패합니다.

### 응답 모델 비활성화 { #disable-response-model }

#### Union { #union }

You can declare that a variable can be any of **several types**, for example, an `int` or a `str`.

To define it you use the <dfn title='also called "bitwise or operator", but that meaning is not relevant here'>vertical bar (`|`)</dfn> to separate both types.

This is called a "union", because the variable can be anything in the union of those two sets of types.

pkg go/types, method (*TypeParamList) At(int) *TypeParam
pkg go/types, method (*TypeParamList) Len() int
pkg go/types, method (*Union) Len() int
pkg go/types, method (*Union) String() string
pkg go/types, method (*Union) Term(int) *Term
pkg go/types, method (*Union) Underlying() Type
pkg go/types, type ArgumentError struct
pkg go/types, type ArgumentError struct, Err error
pkg go/types, type ArgumentError struct, Index int

            .add(Range.closedOpen(5, 10))
            .add(Range.closedOpen(12, 15))
            .add(Range.openClosed(15, 17))
            .add(Range.open(19, 20))
            .build();

    assertThat(RANGE_SET_ONE.union(RANGE_SET_TWO)).isEqualTo(expected);
  }

  public void testIntersection() {
    RangeSet<Integer> expected =
        ImmutableRangeSet.<Integer>builder()
            .add(Range.closed(2, 3))

def is_union_of_base_models(field_type: Any) -> bool:
    """Check if field type is a Union where all members are BaseModel subclasses."""
    from fastapi.types import UnionType

    origin = get_origin(field_type)

    # Check if it's a Union type (covers both typing.Union and types.UnionType in Python 3.10+)
    if origin is not Union and origin is not UnionType:
        return False

    union_args = get_args(field_type)