Cannot find reference self.loadFinished.connect when trying to execute scripts in HTML pages

Question

I'm trying to build a PyQT5 class that will execute s embedded within it.

Here's the code:

class Render(QWebPage):

def __init__(self, html):
    self.html = None
    self.app = QApplication(sys.argv)
    QWebPage.__init__(self)
    self.loadFinished.connect(self._loadFinished)
    self.mainFrame().setHtml(html)
    self.app.exec_()

def _loadFinished(self, result):
    self.html = self.mainFrame().toHtml()
    self.app.quit()

That connect method is unreferencable, here's what I imported:

from PyQt5.QtWidgets import QApplication 
from PyQt5.QtCore import QUrl
from PyQt5.QtWebKitWidgets import QWebPage

Am I missing something?