code: def get_experiment(self, name, variants):
          
          try:
              return self.experiment_factory(model.Experiment.get_by(name=name))
          finally:
              self.Session.close()
docs: Retrieve an experiment by its name and variants (assuming it exists).
  
          :param name a unique string name for the experiment
          :param variants a list of strings, each with a unique variant name
  
          Returns a ``cleaver.experiment.Experiment`` or ``None``