I suggest to drop all ClearML/Trains backward compatibility as ClearML is v1.X since 1.5 year and no one should be using trains v0.16 (the last version of trains).

Let's do the following:

• remove TrainsLogger, TrainsSaver code and tests
• remove all trains package backward compatility. For example,

  ignite/ignite/contrib/handlers/clearml_logger.py

  Lines 118 to 121 in 4bdf243

  	try:
  	# Backwards-compatibility for legacy Trains SDK
  	from trains import Task
  	from trains.binding.frameworks.tensorflow_bind import WeightsGradientHistHelper