TestQButtonGroup.py

from PyQt5.QtCore import *
from PyQt5.QtWidgets import *
import sys

app = QApplication(sys.argv)
w = QWidget()
w.setLayout(QVBoxLayout())
skillP = QCheckBox("Passive")
skillCb = QCheckBox("Combat")
skillCm = QCheckBox("Command")
skillP.setChecked(True)
addskillG = QButtonGroup()
addskillG.addButton(skillP)
addskillG.addButton(skillCm)
addskillG.addButton(skillCb)

w.layout().addWidget(skillP)
w.layout().addWidget(skillCm)
w.layout().addWidget(skillCb)

w.show()
sys.exit(app.exec_())