Merge zero optimizers functions

Closes #89 (closed)

dan/manager/training.py

@@ -532,10 +532,7 @@ class GenericTrainingManager:
 
     def zero_optimizers(self, set_to_none=True):
         for model_name in self.optimizers:
-            self.zero_optimizer(model_name, set_to_none)
-
-    def zero_optimizer(self, model_name, set_to_none=True):
-        self.optimizers[model_name].zero_grad(set_to_none=set_to_none)
+            self.optimizers[model_name].zero_grad(set_to_none=set_to_none)
 
     def train(self, mlflow_logging=False):
         """