def get_exchange_rates(self, obj):
rates = {}
for to_token in self.context.get('exchange_pairs', []):
if to_token != obj:
try:
rate = Exchange.get_exchange_rate(obj, to_token)
rates[to_token.symbol] = rate
except SubexchangeNotFound:
pass
return rates
def get_exchange_rate(user: User, from_token: Token):
to_token = user.get_reserve_token()
if from_token == to_token:
return None
exchange = Exchange()
return exchange.get_exchange_rate(from_token, to_token)