flake8 passing, use pathlib in lieu of os.path to accommodate windows/mac OS

freqtrade/freqai/strategy_bridge.py

@@ -3,10 +3,10 @@ from freqtrade.resolvers.freqaimodel_resolver import FreqaiModelResolver
 
 class CustomModel:
     """
-    A bridge between the user defined IFreqaiModel class 
+    A bridge between the user defined IFreqaiModel class
     and the strategy.
     """
 
-    def __init__(self,config):
+    def __init__(self, config):
 
         self.bridge = FreqaiModelResolver.load_freqaimodel(config)