How to use the blacksheep.exceptions.BadRequest function in blacksheep

required: bool = True,
                 converter: Optional[Callable] = None):
        self.expected_type = expected_type
        self.required = required
        self.converter = converter
        self.name = None

    @abstractmethod
    async def get_value(self, request: Request) -> T:
        ...

    def __repr__(self):
        return f'<{self.__class__.__name__} {self.expected_type} at {id(self)}>'


class MissingBodyError(BadRequest):

    def __init__(self):
        super().__init__('Missing body payload')


class MissingParameterError(BadRequest):

    def __init__(self, name: str, source: str):
        super().__init__(f'Missing parameter `{name}` from {source}')


class InvalidRequestBody(BadRequest):

    def __init__(self, description: Optional[str] = 'Invalid body payload'):
        super().__init__(description)

def _default_bool_converter(value: str):
    if value in {'1', 'true'}:
        return True

    if value in {'0', 'false'}:
        return False

    # bad request: expected a bool value, but
    # got something different that is not handled
    raise BadRequest(f'Expected a bool value for a parameter, but got {value}.')

def __call__(self, request):
        value = get_param(request, self.name)

        if value is None or value == '':
            if self.is_optional:
                return None

            raise BadRequest(f'missing parameter: {self.name}.')

        if self.annotation is str:
            return unwrap(value)

        return value

# http://svn.tools.ietf.org/svn/wg/httpbis/specs/rfc7233.html#rfc.section.3.1
    # A server must ignore a Range header field received with a request method other than GET
    if request.method != 'GET':
        return None

    # NB: only the first Range request header is taken into consideration;
    # if the HTTP contains several Range headers, only the first is used
    range_header = request.get_first_header(b'range')

    if not range_header:
        return None

    try:
        value = Range.parse(range_header)
    except InvalidRangeValue:
        raise BadRequest('Invalid Range header')
    else:
        # An origin server must ignore a Range header field that contains a range unit it does not understand.
        if value.unit != 'bytes':
            return None

        return value

@abstractmethod
    async def get_value(self, request: Request) -> T:
        ...

    def __repr__(self):
        return f'<{self.__class__.__name__} {self.expected_type} at {id(self)}>'


class MissingBodyError(BadRequest):

    def __init__(self):
        super().__init__('Missing body payload')


class MissingParameterError(BadRequest):

    def __init__(self, name: str, source: str):
        super().__init__(f'Missing parameter `{name}` from {source}')


class InvalidRequestBody(BadRequest):

    def __init__(self, description: Optional[str] = 'Invalid body payload'):
        super().__init__(description)


class MissingConverterError(Exception):

    def __init__(self, expected_type, binder_type):
        super().__init__(f'A default converter for type `{str(expected_type)}` is not configured. '
                         f'Please define a converter method for this binder ({binder_type.__name__}).')

def parse_value(value, desired_type: type, param_name: str):
    try:
        if desired_type is bool:
            return bool(int(value))
        if desired_type in {int, float}:
            return desired_type(value)
        return value
    except ValueError:
        raise BadRequest(f'invalid parameter "{param_name}". '
                         f'The value cannot be parsed as {desired_type.__name__}.')

return f'<{self.__class__.__name__} {self.expected_type} at {id(self)}>'


class MissingBodyError(BadRequest):

    def __init__(self):
        super().__init__('Missing body payload')


class MissingParameterError(BadRequest):

    def __init__(self, name: str, source: str):
        super().__init__(f'Missing parameter `{name}` from {source}')


class InvalidRequestBody(BadRequest):

    def __init__(self, description: Optional[str] = 'Invalid body payload'):
        super().__init__(description)


class MissingConverterError(Exception):

    def __init__(self, expected_type, binder_type):
        super().__init__(f'A default converter for type `{str(expected_type)}` is not configured. '
                         f'Please define a converter method for this binder ({binder_type.__name__}).')


class FromBody(Binder):
    _excluded_methods = {'GET', 'HEAD', 'TRACE'}

    def __init__(self,

async def get_value(self, request: Request) -> T:
        raw_value = self.get_raw_value(request)
        try:
            value = self.converter(raw_value)
        except (ValueError, BadRequest):
            raise BadRequest(f'Invalid value for parameter `{self.name}`; expected {self.expected_type}')

        if value is None and self.required:
            raise MissingParameterError(self.name, self.source_name)

        if not self.required and self._empty_iterable(value):
            return None

        return value