def format_conversion(self, from_amt, from_curr, to_curr):

        to_amt = self.cost_rates.convert(from_amt, from_curr, to_curr)

        return "{}\n{}".format(

            self.format_denominated_rate(from_amt, from_curr, to_curr),

            self.format_denominated_rate(to_amt, to_curr, None),

        )

class BeancountFormatter(LedgerFormatter):

    COST_FMT = '{{{}}}'

    def __init__(self, cost_rates, price_rates=None,

                 rate_precision=5, denomination=None):

        super().__init__(

            cost_rates,

            price_rates,

            (),

            rate_precision,

            denomination,

        )

    def price_rate(self, from_amt, from_curr, to_curr):

        if self.price_rates is None:

            return None

        else:

            return self.price_rates.convert(from_amt, from_curr, to_curr)

class Formats(enum.Enum):

def check_fx_amount(config, lines, amount, cost, fx_code, fx_sign=None, price=None):

    if price is None:

        price = cost

    rate_fmt = f'{{}} {re.escape(fx_code)}'

    cost = re.escape(cost) + r'\d*'

    price = re.escape(price) + r'\d*'

    if config.args.output_format is oxrhist.Formats.LEDGER:

        if fx_sign is not None and fx_code in config.args.signed_currencies:

            rate_fmt = f'{re.escape(fx_sign)}{{}}'

        cost_re = '{{={}}}'.format(rate_fmt.format(cost))

        price_re = ' @ {}'.format(rate_fmt.format(price))

    else:

        cost_re = '{{{}}}'.format(rate_fmt.format(cost))

        if config.args.from_date is None:

            price_re = ''

        else:

            price_re = ' @ {}'.format(rate_fmt.format(price))

    pattern = r'^{} {}{}$'.format(re.escape(amount), cost_re, price_re)

    line = next(lines, "<EOF>")

    assert re.match(pattern, line)

def check_nonfx_amount(config, lines, amount, code=None, sign=None):

    if config.args.output_format is oxrhist.Formats.LEDGER:

        if code is None:

            code = 'USD'

            sign = '$'

        if code in config.args.signed_currencies and sign is not None:

            expected = f'{sign}{amount}\n'

        else:

            expected = f'{amount} {code}\n'

    else:

    assert next(lines, "<EOF>") == expected

def test_rate_list(single_responder, output, any_date):

    config = build_config(single_responder, any_date)

    lines = lines_from_run(config, output)

    assert next(lines).startswith('1 AED = 0.27229')

    assert next(lines) == '1 USD = 3.67246 AED\n'

    assert next(lines).startswith('1 ALL = 0.0069189')

    assert next(lines) == '1 USD = 144.529793 ALL\n'

    assert next(lines).startswith('1 ANG = 0.55865')

    assert next(lines) == '1 USD = 1.79 ANG\n'