add kwargs, reduce duplicated code

freqtrade/freqai/prediction_models/CatboostClassifier.py

@@ -2,6 +2,7 @@ import logging
 from typing import Any, Dict
 
 from catboost import CatBoostClassifier, Pool
+
 from freqtrade.freqai.data_kitchen import FreqaiDataKitchen
 from freqtrade.freqai.prediction_models.BaseClassifierModel import BaseClassifierModel
 
@@ -16,7 +17,7 @@ class CatboostClassifier(BaseClassifierModel):
     has its own DataHandler where data is held, saved, loaded, and managed.
     """
 
-    def fit(self, data_dictionary: Dict, dk: FreqaiDataKitchen) -> Any:
+    def fit(self, data_dictionary: Dict, dk: FreqaiDataKitchen, **kwargs) -> Any:
         """
         User sets up the training and test data to fit their desired model here
         :params:
@@ -36,10 +37,7 @@ class CatboostClassifier(BaseClassifierModel):
             **self.model_training_parameters,
         )
 
-        if dk.pair not in self.dd.model_dictionary or not self.continual_learning:
-            init_model = None
-        else:
-            init_model = self.dd.model_dictionary[dk.pair]
+        init_model = self.get_init_model(dk.pair)
 
         cbr.fit(train_data, init_model=init_model)