# -*- coding: utf-8 -*-
import sys
from PySide2 import QtWidgets

app = QtWidgets.QApplication(sys.argv)

tree_widget = QtWidgets.QTreeWidget()
tree_widget.setColumnCount(3)

layout = QtWidgets.QGridLayout()
layout.addWidget(tree_widget)

window = QtWidgets.QWidget()
window.setLayout(layout)

window.show()

sys.exit(app.exec_())