Added leverage enums

freqtrade/enums/tradingmode.py

@@ -0,0 +1,11 @@
+from enum import Enum
+
+
+class TradingMode(Enum):
+    """
+        Enum to distinguish between
+        spot, margin, futures or any other trading method
+    """
+    SPOT = "spot"
+    MARGIN = "margin"
+    FUTURES = "futures"