Add some error cases tests
Calculate exp_desc value at Running time
Simplify experiment.load_experiment
Remove unnecessary error print in main_cli test
Simplify check_experiment_state and add more verbose output on states
Reduce some code complexity flake8
Separate expand_short_nodes_list in two functions to increase readability
Cut rest call in two functions to remove some complexity
Add flake8 to tox
Add flake8 to tox, and correct other python versions errors