QListView remain empty

Question

i want to display list data in QListView but it didn't show anything and remain empty after running the code. i don't get any error message so i don't know what is wrong with my code. anyone could help me?

def process_data(self, fn):
    self.model.read_data(self.fn)
    self.model.preprocess_data()
    self.model.polarity()
    dataset = self.model.dataset
    dataset = dataset.tolist()
    data_list = []
    for i in range(1, 15):
        temp = []
        temp.append(dataset[i])
        data_list.append(temp)
    data_list = np.array(data_list)
    print(data_list) #everything is fine until here but idk after
    data_model = ShowList(data_list)
    self.preprocessedresult = QtWidgets.QListView()
    self.preprocessedresult.setModel(data_model)

    


class ShowList(QtCore.QAbstractListModel):

def __init__(self, data):
    QtCore.QAbstractListModel.__init__(self)
    self.datalist = data
    
def data(self, index, role):
    if index.isValid() and role == Qt.DisplayRole:
        val = self.datalist[index.row()]
        return val
    
def row_count(self, index):
    return len(self.datalist)