* good reference implementation. As with {@code IteratorTester}, a concrete subclass must provide
 * target iterators on demand. It also requires three additional constructor parameters: {@code
 * elementsToInsert}, the elements to be passed to {@code set()} and {@code add()} calls; {@code
 * features}, the features supported by the iterator; and {@code expectedElements}, the elements the

                            },
                        },
                    },
                    "summary": "Read Items",
                    "operationId": "read_items_items__get",
                    "parameters": [
                        {
                            "required": False,
                            "schema": IsDict(
                                {

                            },
                        },
                    },
                    "summary": "Read Items",
                    "operationId": "read_items_items__item_id__put",
                    "parameters": [
                        {
                            "required": True,
                            "schema": {
                                "title": "Item Id",
                                "type": "string",

                            },
                        },
                    },
                    "summary": "Read Items",
                    "operationId": "read_items_items__get",
                    "parameters": [
                        {
                            "required": False,
                            "schema": IsDict(
                                {

                            },
                        },
                    },
                    "summary": "Read User Item",
                    "operationId": "read_user_item_items__item_id__get",
                    "parameters": [
                        {
                            "required": True,
                            "schema": {"title": "Item Id", "type": "string"},
                            "name": "item_id",

@needs_pydanticv1
def test_union_scalar_list():
    # For coverage
    # TODO: there might not be a current valid code path that uses this, it would
    # potentially enable query parameters defined as both a scalar and a list
    # but that would require more refactors, also not sure it's really useful
    from fastapi._compat import is_pv1_scalar_field

    field_info = FieldInfo()
    field = ModelField(

                            },
                        },
                    },
                    "summary": "Read File",
                    "operationId": "read_file_files__file_path__get",
                    "parameters": [
                        {
                            "required": True,
                            "schema": {"title": "File Path", "type": "string"},
                            "name": "file_path",

                            },
                        },
                    },
                    "summary": "Read Items",
                    "operationId": "read_items_items__get",
                    "parameters": [
                        {
                            "required": False,
                            "schema": {
                                "title": "Q",
                                "type": "array",

                            },
                        },
                    },
                    "summary": "Read Items",
                    "operationId": "read_items_items__get",
                    "parameters": [
                        {
                            "required": False,
                            "schema": IsDict(
                                {
                                    "anyOf": [

{!../../docs_src/bigger_applications/app/routers/users.py!}
```

You can think of `APIRouter` as a "mini `FastAPI`" class.

All the same options are supported.

All the same `parameters`, `responses`, `dependencies`, `tags`, etc.

/// tip

In this example, the variable is called `router`, but you can name it however you want.

///