origin_type = get_origin(field.field_info.annotation) or field.field_info.annotation
    if origin_type is Union or origin_type is UnionType:  # Handle optional sequences
        union_args = get_args(field.field_info.annotation)
        for union_arg in union_args:
            if union_arg is type(None):
                continue
            origin_type = get_origin(union_arg) or union_arg
            break

from copy import copy, deepcopy
from dataclasses import dataclass
from typing import (
    Annotated,
    Any,
    ForwardRef,
    Literal,
    Union,
    cast,
    get_args,
    get_origin,
)

from fastapi import params
from fastapi._compat import (
    ModelField,
    RequiredParam,
    Undefined,
    copy_field_info,
    create_body_model,