slot of QClipboard::dataChanged() was called twice

[redstoneleo]

The slot detectClipboardUrl of QClipboard::dataChanged() was called twice sometimes when I copy url in Google Chrome's address bar in this code, tested with PyQt5.7,Python3.5 on Win7 32bit, also on Linux Mint 18, while I need the slot to be called only once , is this a bug ? any solutions ?

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


class MainWindow(QTableView):

    def __init__(self, parent=None):
        super().__init__(parent)
        self.clipboard = QApplication.clipboard()
        self.clipboard.dataChanged.connect(self.detectClipboardUrl)  

    @pyqtSlot()
    def detectClipboardUrl(self):
        print('detectClipboardUrl')
        clipboardText = self.clipboard.text()
        print(clipboardText)


if __name__ == "__main__":
    app = QApplication(sys.argv)
    ui = MainWindow()
    ui.show()
    sys.exit(app.exec_())