updated get_max_leverage to use new ccxt unified property

freqtrade/exchange/ftx.py

@@ -1,6 +1,6 @@
 """ FTX exchange subclass """
 import logging
-from typing import Any, Dict, List, Optional, Tuple
+from typing import Any, Dict, List, Tuple
 
 import ccxt
 
@@ -168,18 +168,3 @@ class Ftx(Exchange):
         if order['type'] == 'stop':
             return safe_value_fallback2(order, order, 'id_stop', 'id')
         return order['id']
-
-    def fill_leverage_brackets(self):
-        """
-            FTX leverage is static across the account, and doesn't change from pair to pair,
-            so _leverage_brackets doesn't need to be set
-        """
-        return
-
-    def get_max_leverage(self, pair: Optional[str], nominal_value: Optional[float]) -> float:
-        """
-            Returns the maximum leverage that a pair can be traded at, which is always 20 on ftx
-            :param pair: Here for super method, not used on FTX
-            :nominal_value: Here for super method, not used on FTX
-        """
-        return 20.0