Miscellaneous funding fee changes. Abandoning for a new method of tracking funding fee

freqtrade/exchange/binance.py

@@ -1,6 +1,6 @@
 """ Binance exchange subclass """
 import logging
-from typing import Dict
+from typing import Dict, Optional
 
 import ccxt
 
@@ -89,3 +89,17 @@ class Binance(Exchange):
                 f'Could not place sell order due to {e.__class__.__name__}. Message: {e}') from e
         except ccxt.BaseError as e:
             raise OperationalException(e) from e
+
+    # https://www.binance.com/en/support/faq/360033525031
+    def get_funding_fee(
+        self,
+        contract_size: float,
+        mark_price: float,
+        rate: Optional[float],
+        # index_price: float,
+        # interest_rate: float
+    ):
+        assert isinstance(rate, float)
+        nominal_value = mark_price * contract_size
+        adjustment = nominal_value * rate
+        return adjustment