TBD

def _build(self, input_modules, middle_modules, head_modules):
        """
        TBD
        """
        self.input_layer = self._build_input_layer(input_modules)
        self.middle_layers = self._build_middle_layers(middle_modules)
        self.heads = self._build_task_heads(head_modules)

        # Construct loss module
        reduction = self.config["train_config"]["loss_fn_reduction"]
        self.criteria = SoftCrossEntropyLoss(reduction=reduction)