Robust mlflow requests

Requires !57 (merged)

Closes #28 (closed)

dan/manager/training.py

@@ -23,8 +23,10 @@ from tqdm import tqdm
 from dan.manager.metrics import MetricManager
 from dan.ocr.utils import LM_ind_to_str
 from dan.schedulers import DropoutScheduler
+
 try:
     import mlflow
+
     from dan.mlflow import logging_metrics, logging_tags_metrics
 except ImportError:
     pass