code: def get_buy_price(self, **params):
          
          currency_pair = params.get('currency_pair', 'BTC-USD')
          response = self._get('v2', 'prices', currency_pair, 'buy', params=params)
          return self._make_api_object(response, APIObject)
docs: https://developers.coinbase.com/api/v2#get-buy-price