Функции в pyqt5

from for_mix import Ui_MainWindow
import sys
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtCore import Qt
from datetime import datetime
 
 
class TableModel(QtCore.QAbstractTableModel):
    def __init__(self, data):
        super(TableModel, self).__init__()
        self._data = data
        self.horizontalHeaderLabels = []
 
    def setHorizontalHeaderLabels(self, horizontalHeaderLabels):
        self.horizontalHeaderLabels = horizontalHeaderLabels
 
    def headerData(self, section, orientation, role=Qt.DisplayRole):
        if (orientation == Qt.Horizontal and role == Qt.DisplayRole and len(
                self.horizontalHeaderLabels) == self.columnCount(None)):
            return self.horizontalHeaderLabels[section]
        return super().headerData(section, orientation, role)
 
    def data(self, index, role):
        if role == Qt.DisplayRole:
            # Get the raw value
            value = self._data[index.row()][index.column()]
 
            # Perform per-type checks and render accordingly.
            if isinstance(value, datetime):
                # Render time to YYY-MM-DD.
                return value.strftime("%Y-%m-%d")
 
            if isinstance(value, float):
                # Render float to 2 dp
                return "%.2f" % value
 
            if isinstance(value, str):
                # Render strings with quotes
                return '"%s"' % value
 
            # Default (anything not captured above: e.g. int)
            return value
 
        if role == Qt.ForegroundRole:
            value = self._data[index.row()][index.column()]
 
            if (
                    (isinstance(value, int) or isinstance(value, float))
                    and value < 0
            ):
                return QtGui.QColor('red')
 
    def rowCount(self, index):
        # The length of the outer list.
        return len(self._data)
 
    def columnCount(self, index):
        # The following takes the first sub-list, and returns
        # the length (only works if all rows are an equal length)
        return len(self._data[0])
 
 
class MainWindow(QtWidgets.QMainWindow):
    def __init__(self):
        super(MainWindow, self).__init__()
        self.ui = Ui_MainWindow()
        self.ui.setupUi(self)
 
        self.table = QtWidgets.QTableView()
        self.setWindowTitle("Шахматисты")
        self.resize(800, 600)
 
        data = [
            [4, 9, 'hello', 4, 9, 'hello'],
            [1, 0, 0, 4, 9, 'hello'],
            [3, 5, 0, 4, 9, 'hello'],
            [3, -3, 2, 4, 9, 'hello'],
            [7, 8, 9, 4, 9, 'hello'],
        ]
 
        self.model = TableModel(data)
        self.model.setHorizontalHeaderLabels(['Name', 'Age', 'Sex', 'Name', 'Age', 'Sex'])
        self.table.setModel(self.model)
        self.table.setMinimumSize(800, 400)
        self.table.setMaximumSize(800, 400)
        self.setCentralWidget(self.table)
        self.button1 = QtWidgets.QPushButton('ОЧИСТИТЬ', self)
        self.button1.resize(100, 60)
        self.button1.move(30, 420)
        self.button2 = QtWidgets.QPushButton('УДАЛИТЬ', self)
        self.button2.resize(100, 60)
        self.button2.move(30, 500)
        self.button3 = QtWidgets.QPushButton('ДОБАВИТЬ', self)
        self.button3.resize(100, 60)
        self.button3.move(150, 420)
        self.button4 = QtWidgets.QPushButton('СОРТИРОВКА', self)
        self.button4.resize(100, 60)
        self.button4.move(150, 500)
        self.button5 = QtWidgets.QPushButton('НАЙТИ', self)
        self.button5.resize(100, 60)
        self.button5.move(270, 420)
        self.button6 = QtWidgets.QPushButton('ИНФО', self)
        self.button6.resize(100, 60)
        self.button6.move(270, 500)
        self.lineEdit = QtWidgets.QLineEdit(self)
        self.lineEdit.resize(350, 140)
        self.lineEdit.move(400, 420)
        self.ui.pushButton.clicked.connect(self.function1)
 
    def function1(self):
        self.ui.lineEdit.setPlaceholderText("Hi")
 
 
app = QtWidgets.QApplication([])
application = MainWindow()
application.show()
 
sys.exit(app.exec())

self.data = [[]]