panic(err)
			}
			enc = e
		})
		return enc
	}
	return
}

// EncodeData encodes the given data and returns the erasure-coded data.
// It returns an error if the erasure coding failed.
func (e *Erasure) EncodeData(ctx context.Context, data []byte) ([][]byte, error) {
	if len(data) == 0 {
		return make([][]byte, e.dataBlocks+e.parityBlocks), nil
	}
	encoded, err := e.encoder().Split(data)

            <multiplicity>*</multiplicity>
          </association>
          <description><![CDATA[Restricts the classes/resources from the current artifact's CoreExtension class realm that are exposed. Values ending with ".*" expose all classes/resources which are directly contained in the given package in binary form. 

It will be defined in OpenAPI with `anyOf`.

To do that, use the standard Python type hint <a href="https://docs.python.org/3/library/typing.html#typing.Union" class="external-link" target="_blank">`typing.Union`</a>:

!!! note

```

!!! note
    Notice that as we communicate with the database using `await`, the *path operation function* is declared with `async`.

### Notice the `response_model=List[Note]`

It uses `typing.List`.

That documents (and validates, serializes, filters) the output data, as a `list` of `Note`s.

## Create notes

Create the *path operation function* to create notes:

```Python hl_lines="61-65"

from typing import Union

from fastapi import FastAPI, Query
from typing_extensions import Annotated

app = FastAPI()


@app.get("/items/")
async def read_items(
    hidden_query: Annotated[Union[str, None], Query(include_in_schema=False)] = None,
):
    if hidden_query:
        return {"hidden_query": hidden_query}
    else:

from typing import Union

from fastapi import FastAPI, Query
from typing_extensions import Annotated

app = FastAPI()


@app.get("/items/")
async def read_items(
    q: Annotated[Union[str, None], Query(min_length=3, max_length=50)] = None,
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

}

// ErasureInfo holds erasure coding and bitrot related information.
type ErasureInfo struct {
	// Algorithm is the string representation of erasure-coding-algorithm
	Algorithm string `json:"algorithm"`
	// DataBlocks is the number of data blocks for erasure-coding
	DataBlocks int `json:"data"`
	// ParityBlocks is the number of parity blocks for erasure-coding
	ParityBlocks int `json:"parity"`

from typing import Any, Dict, Optional, Sequence, Type, Union

from pydantic import BaseModel, create_model
from starlette.exceptions import HTTPException as StarletteHTTPException
from starlette.exceptions import WebSocketException as StarletteWebSocketException
from typing_extensions import Annotated, Doc


class HTTPException(StarletteHTTPException):
    """
    An HTTP exception you can raise in your own code to show errors to the client.

from typing import Any, Callable

from starlette.background import BackgroundTasks as StarletteBackgroundTasks
from typing_extensions import Annotated, Doc, ParamSpec

P = ParamSpec("P")


class BackgroundTasks(StarletteBackgroundTasks):
    """
    A collection of background tasks that will be called after a response has been
    sent to the client.

    Read more about it in the

from typing import (
    Any,
    BinaryIO,
    Callable,
    Dict,
    Iterable,
    Optional,
    Type,
    TypeVar,
    cast,
)

from fastapi._compat import (
    PYDANTIC_V2,
    CoreSchema,
    GetJsonSchemaHandler,
    JsonSchemaValue,
    with_info_plain_validator_function,
)
from starlette.datastructures import URL as URL  # noqa: F401
from starlette.datastructures import Address as Address  # noqa: F401