Вывод изображений сеткой PyQt5, Python 3.5

from PyQt5 import QtWidgets, QtCore
from PyQt5.QtGui import *
from PyQt5.QtCore import *
from PyQt5.Qt import *
from PyQt5.QtWidgets import (QWidget, QHBoxLayout, QLabel, QApplication)
import sys
 
class Example(QWidget):
    def __init__(self):
        super().__init__()
        self.initUI()
 
    def initUI(self):
        hbox = QHBoxLayout(self)
        hbox2 = QHBoxLayout(self)
        #vbox = QtWidgets.QVBoxLayout(self)
        pixmap1 = QPixmap("1.png")
        pixmap2 = QPixmap("1.png")
        pixmap3 = QPixmap("1.png")
        pixmap4 = QPixmap("1.png")
        lbl = QLabel(self)
        lbl2 = QLabel(self)
        lbl3 = QLabel(self)
        lbl4 = QLabel(self)
        lbl.setPixmap(pixmap1)
        lbl2.setPixmap(pixmap2)
        lbl3.setPixmap(pixmap3)
        lbl4.setPixmap(pixmap4)
        hbox.addWidget(lbl)
        hbox.addWidget(lbl2)
        hbox2.addWidget(lbl3)
        hbox2.addWidget(lbl4)
        hbox.setAlignment(Qt.AlignLeft)
        hbox2.setAlignment(Qt.AlignLeft)
        self.setLayout(hbox)
        self.setLayout(hbox2)
        self.show()
 
if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    window = Example()
    window.setWindowTitle("Primer")
    window.resize(400, 100)
    sys.exit(app.exec_())