Add some type hints

freqtrade/edge/edge_positioning.py

@@ -1,7 +1,7 @@
 # pragma pylint: disable=W0603
 """ Edge positioning package """
 import logging
-from typing import Any, Dict, NamedTuple
+from typing import Any, Dict, List, NamedTuple
 
 import arrow
 import numpy as np
@@ -181,7 +181,7 @@ class Edge:
                            'strategy stoploss is returned instead.')
             return self.strategy.stoploss
 
-    def adjust(self, pairs) -> list:
+    def adjust(self, pairs: List[str]) -> list:
         """
         Filters out and sorts "pairs" according to Edge calculated pairs
         """