@@ -67,6 +67,11 @@ class Balance(Mapping[str, data.Amount]):
amounts.sort(key=lambda amt: abs(amt.number), reverse=True)
return ', '.join(str(amount) for amount in amounts)
def __neg__(self) -> 'Balance':
return type(self)(
(key, -amt) for key, amt in self.items()
)
def __getitem__(self, key: str) -> data.Amount:
return data.Amount(self._currency_map[key], key)