diff --git a/bfxapi/rest/BfxRestInterface.py b/bfxapi/rest/BfxRestInterface.py
index 375d0d6..35153fc 100644
--- a/bfxapi/rest/BfxRestInterface.py
+++ b/bfxapi/rest/BfxRestInterface.py
@@ -30,20 +30,24 @@ class BfxRestInterface(object):
         return serializers.PlatformStatus.parse(*self.__GET("platform/status"))
 
     def tickers(self, symbols: List[str]) -> List[Union[TradingPairTicker, FundingCurrencyTicker]]:
+        data = self.__GET("tickers", params={ "symbols": ",".join(symbols) })
+        
         return [
             {
                 "t": serializers.TradingPairTicker.parse,
                 "f": serializers.FundingCurrencyTicker.parse
             }[subdata[0][0]](*subdata)
 
-            for subdata in self.__GET("tickers", params={ "symbols": ",".join(symbols) })
+            for subdata in data
         ]
 
     def ticker(self, symbol: str) -> Union[TradingPairTicker, FundingCurrencyTicker]:
+        data = self.__GET(f"ticker/{symbol}")
+
         return {
             "t": serializers.TradingPairTicker.parse,
             "f": serializers.FundingCurrencyTicker.parse
-        }[symbol[0]](*self.__GET(f"ticker/{symbol}"), skip=["SYMBOL"])
+        }[symbol[0]](*data, skip=["SYMBOL"])
 
     def tickers_history(self, symbols: List[str], start: Optional[int] = None, end: Optional[int] = None, limit: Optional[int] = None) -> TickerHistories:
         params = {
@@ -51,29 +55,35 @@ class BfxRestInterface(object):
             "start": start, "end": end,
             "limit": limit
         }
+
+        data = self.__GET("tickers/hist", params=params)
         
-        return [ serializers.TickerHistory.parse(*subdata) for subdata in self.__GET("tickers/hist", params=params) ]
+        return [ serializers.TickerHistory.parse(*subdata) for subdata in data ]
 
     def trades(self, symbol: str, limit: Optional[int] = None, start: Optional[str] = None, end: Optional[str] = None, sort: Optional[int] = None) -> Union[TradingPairTrades, FundingCurrencyTrades]:
         params = { "symbol": symbol, "limit": limit, "start": start, "end": end, "sort": sort }
         
+        data = self.__GET(f"trades/{symbol}/hist", params=params)
+
         return [
             {
                 "t": serializers.TradingPairTrade.parse,
                 "f": serializers.FundingCurrencyTrade.parse
             }[symbol[0]](*subdata)
 
-            for subdata in self.__GET(f"trades/{symbol}/hist", params=params)
+            for subdata in data
         ]
 
     def book(self, symbol: str, precision: str, len: Optional[int] = None) -> Union[TradingPairBooks, FundingCurrencyBooks, TradingPairRawBooks, FundingCurrencyRawBooks]:
+        data = self.__GET(f"book/{symbol}/{precision}", params={ "len": len })
+        
         return [
             {
                 "t": precision == "R0" and serializers.TradingPairRawBook.parse or serializers.TradingPairBook.parse,
                 "f": precision == "R0" and serializers.FundingCurrencyRawBook.parse or serializers.FundingCurrencyBook.parse,
             }[symbol[0]](*subdata)
 
-            for subdata in self.__GET(f"book/{symbol}/{precision}", params={ "len": len })
+            for subdata in data
         ]
 
     def stats(
@@ -81,47 +91,48 @@ class BfxRestInterface(object):
         resource: str, section: Literal["hist", "last"],
         sort: Optional[int] = None, start: Optional[str] = None, end: Optional[str] = None, limit: Optional[int] = None
     ) -> Union[Stat, Stats]:
-        endpoint = f"stats1/{resource}/{section}"
-
         params = { "sort": sort, "start": start, "end": end, "limit": limit }
 
+        data = self.__GET(f"stats1/{resource}/{section}", params=params)
+
         if section == "last":
-            return serializers.Stat.parse(*self.__GET(endpoint, params=params))
-        return [ serializers.Stat.parse(*subdata) for subdata in self.__GET(endpoint, params=params) ]
+            return serializers.Stat.parse(*data)
+        return [ serializers.Stat.parse(*subdata) for subdata in data ]
 
     def candles(
         self,
         resource: str, section: Literal["hist", "last"],
         sort: Optional[int] = None, start: Optional[str] = None, end: Optional[str] = None, limit: Optional[int] = None
     ) -> Union[Candle, Candles]:
-        endpoint = f"candles/{resource}/{section}"
-
         params = { "sort": sort, "start": start, "end": end, "limit": limit }
 
+        data = self.__GET(f"candles/{resource}/{section}", params=params)
+
         if section == "last":
-            return serializers.Candle.parse(*self.__GET(endpoint, params=params))
-        return [ serializers.Candle.parse(*subdata) for subdata in self.__GET(endpoint, params=params) ]
+            return serializers.Candle.parse(*data)
+        return [ serializers.Candle.parse(*subdata) for subdata in data ]
 
-    def derivatives_status(self, type: str, keys: Optional[List[str]] = None) -> DerivativeStatuses:
-        params = None
-        
-        if keys != None:
-            params = { "keys": ",".join(keys) }
+    def derivatives_status(self, type: str, keys: List[str] = None) -> DerivativeStatuses:
+        params = { "keys": ",".join(keys) }
 
-        return [ serializers.DerivativesStatus.parse(*subdata) for subdata in self.__GET(f"status/{type}", params=params) ]
+        data = self.__GET(f"status/{type}", params=params)
+
+        return [ serializers.DerivativesStatus.parse(*subdata) for subdata in data ]
 
     def derivatives_status_history(
         self, 
         type: str, symbol: str,
         sort: Optional[int] = None, start: Optional[str] = None, end: Optional[str] = None, limit: Optional[int] = None
     ) -> DerivativeStatuses: 
-        endpoint = f"status/{type}/{symbol}/hist"
-
         params = { "sort": sort, "start": start, "end": end, "limit": limit }
 
-        return [ serializers.DerivativesStatus.parse(*subdata, skip=[ "KEY" ]) for subdata in self.__GET(endpoint, params=params) ]
+        data = self.__GET(f"status/{type}/{symbol}/hist", params=params)
+
+        return [ serializers.DerivativesStatus.parse(*subdata, skip=[ "KEY" ]) for subdata in data ]
 
     def liquidations(self, sort: Optional[int] = None, start: Optional[str] = None, end: Optional[str] = None, limit: Optional[int] = None) -> Liquidations:
         params = { "sort": sort, "start": start, "end": end, "limit": limit }
 
-        return [ serializers.Liquidation.parse(*subdata[0]) for subdata in self.__GET("liquidations/hist", params=params) ]
\ No newline at end of file
+        data = self.__GET("liquidations/hist", params=params)
+
+        return [ serializers.Liquidation.parse(*subdata[0]) for subdata in data ]
\ No newline at end of file