# TODO: import from typing when deprecating Python 3.9
from typing_extensions import Annotated, Doc


class OAuth2PasswordRequestForm:
    """
    This is a dependency class to collect the `username` and `password` as form data
    for an OAuth2 password flow.

    The OAuth2 specification dictates that for a password flow the data should be

from fastapi.logger import logger
from fastapi.security.base import SecurityBase
from fastapi.security.oauth2 import OAuth2, SecurityScopes
from fastapi.security.open_id_connect_url import OpenIdConnect
from fastapi.utils import create_response_field, get_path_param_names
from pydantic.fields import FieldInfo
from starlette.background import BackgroundTasks as StarletteBackgroundTasks

    * Send the invoice to the client.
    * Collect the money from the client.
    * Send a notification back to the API user (the external developer), as a callback.
        * At this point is that the API will somehow send a POST request to the
            external API with the notification of the invoice event
            (e.g. "payment successful").
    """
    # Send the invoice, collect the money, send the notification (the callback)