NN.on_validation_epoch_end() missing 1 required positional argument: 'validation_step_outputs'

[PerniDevs]

Hello I'm dealing with the error mentioned in the title, My code is as follows:

class NN(pl.LightningModule):  # here nn.Module is replaced by LightningModule
        def __init__(self, num_classes, class_to_idx, device ,learning_rate = 0.1, dropout = 0.25):

        ...

        def on_train_epoch_end(self, training_step_outputs):
                """Calculate epoch level metrics for the train set"""
                avg_train_loss = self.train_loss.compute()
                avg_train_acc = self.train_acc.compute()
                # conf_mat = self.confusion_matrix.compute()
                self.log("train/loss", avg_train_loss, prog_bar=True)
                self.log("train/acc", avg_train_acc, prog_bar=True)
                # self.log("train/confusion_matrix", conf_mat)
                self.log("step", self.current_epoch)
        
            def on_validation_epoch_end(self, validation_step_outputs):
                """Calculate epoch level metrics for the validation set"""
                avg_val_loss = self.valid_loss.compute()
                avg_val_acc = self.valid_acc.compute()
                # conf_mat = self.confusion_matrix.compute()
                self.log("valid/loss", avg_val_loss, prog_bar=True)
                self.log("valid/acc", avg_val_acc, prog_bar=True)
                # self.log("valid/confusion_matrix", conf_mat)
                self.log("step", self.current_epoch)
        
            def on_test_epoch_end(self, test_step_outputs):
                """Calculate epoch level metrics for the validation set"""
                avg_test_loss = self.test_loss.compute()
                avg_test_acc = self.test_acc.compute()
                # conf_mat = self.confusion_matrix.compute()
                self.log("test/loss", avg_test_loss, prog_bar=True)
                self.log("test/acc", avg_test_acc, prog_bar=True)
                # self.log("test/confusion_matrix", conf_mat)
                self.log("step", self.current_epoch)
                ...

I'm already using the validation_step_outputs, and is not working either. By the way I'm using colab so the pytorch lightning version is up to date