Pyqt5在两个小部件之间画一条线

from PyQt5.QtWidgets import QApplication, QWidget
from PyQt5.QtGui import QPainter, QPen
from PyQt5.QtCore import Qt

class MyWidget(QWidget):
    def paintEvent(self, event):
        painter = QPainter(self)
        pen = QPen(Qt.black, 2, Qt.SolidLine)
        painter.setPen(pen)
        painter.drawLine(10, 10, 100, 100)

app = QApplication([])
widget = MyWidget()
widget.show()
app.exec_()