code: def evaluation_step(self, Xi, training=False):
          
          with torch.set_grad_enabled(training):
              self.module_.train(training)
              return self.infer(Xi)
docs: Perform a forward step to produce the output used for
          prediction and scoring.
  
          Therefore the module is set to evaluation mode by default
          beforehand which can be overridden to re-enable features
          like dropout by setting ``training=True``.