from PyQt5.QtWidgets import QApplication, QMainWindow, QComboBox, QWidget
from PyQt5.QtCore import pyqtSlot, pyqtSignal

def int_slot(arg):
    print('int_slot', arg, type(arg))

def str_slot(arg):
    print('str_slot', arg, type(arg))

import sys
app = QApplication(sys.argv)
main = QMainWindow()
combobox = QComboBox()

main.setCentralWidget(combobox)

combobox.addItems(['1', '2', '3'])

# Da poslje signal integer:
combobox.currentIndexChanged.connect(int_slot)
# Ali istovredno
combobox.currentIndexChanged[int].connect(int_slot)
# Zaradi tega bo int_slot funkcija dvakrat poveyana, saj ima signal dvakrat
# povezan


# Ce zelimo niz ali string naredimo naslednje:
combobox.currentIndexChanged[str].connect(str_slot)

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