import sys
from PyQt5.QtWidgets import QTreeWidget, QTreeWidgetItem, QApplication, QWidget
if __name__ == '__main__':
    app = 0
    if QApplication.instance():
        app = QApplication.instance()
    else:
        app = QApplication(sys.argv)
    three = [["shishka1"], ["shishka2"], ["shishka3"], ["shishka4"], ["shishka5"]]
    w = QWidget()
    w.resize(700, 700)
    tw = QTreeWidget(w)
    tw.resize(200, 600)
    tw.setColumnCount(1)
    tw.setHeaderLabels(["shishki"])
    for bla in three:
        obj = QTreeWidgetItem(bla)
        for i in range(20):
            obj_child = QTreeWidgetItem([''.join(bla) + "_child_0%s" % str(i + 1)])
            obj.addChild(obj_child)
        tw.addTopLevelItem(obj)
    w.show()
    sys.exit(app.exec_())

 import sys
from PyQt4.QtGui import QTreeWidget, QTreeWidgetItem, QApplication, QWidget
from PyQt4.QtCore import *
if __name__ == '__main__':
    app = 0
    if QApplication.instance():
        app = QApplication.instance()
    else:
        app = QApplication(sys.argv)
    three = [["shishka1"], ["shishka2"], ["shishka3"], ["shishka4"], ["shishka5"]]
    w = QWidget()
    w.resize(700, 700)
    tw = QTreeWidget(w)
    tw.resize(200, 600)
    tw.setColumnCount(1)
    tw.setHeaderLabels(["shishki"])
    for bla in three:
        obj = QTreeWidgetItem(bla)
        obj.setFlags(obj.flags() | Qt.ItemIsUserCheckable)
        obj.setCheckState(0, Qt.Unchecked)
        for i in range(20):
            obj_child = QTreeWidgetItem([''.join(bla) + "_child_0%s" % str(i + 1)])
            obj_child.setFlags(obj_child.flags() | Qt.ItemIsUserCheckable)
            obj_child.setCheckState(0, Qt.Unchecked)
            obj.addChild(obj_child)
        tw.addTopLevelItem(obj)
    w.show()
    sys.exit(app.exec_())