## Attachment


An attachment is bytes with a filename and a content type that a message carries.


Usage

``` python
Attachment(
    filename,
    content_type,
    data,
    content_id,
)
```


[Message.attach()](Message.md#epistole.Message.attach) and [Message.embed()](Message.md#epistole.Message.embed) build one. See ADR-0018.


## Attributes


`filename: str`  
The name the recipient sees.

`content_type: str`  
A bare media type, with no parameters. Within a message it is never a `message/*` or `multipart/*` type, so a transport can write the bytes as base64.

`data: bytes`  
The bytes, which the builder method reads at call time.

`content_id: str | None`  
The name the HTML uses after `cid:` on an inline image, or `None` on an attachment.