Merge pull request #462 from arisliang/patch-1

Remove non-existing parameter description

Author: you-n-g

qlib/contrib/strategy/strategy.py

@@ -148,7 +148,6 @@ def generate_target_weight_position(self, score, current, trade_date):
             pred score for this trade date, index is stock_id, contain 'score' column.
         current : Position()
             current position.
-        trade_exchange : Exchange()
         trade_date : pd.Timestamp
             trade date.
         """