title: PyQt5 returns None value when loading Web page content
body: <p>I am trying to get the content of a web page section. The data in that section is loaded dynamically by javascript. I found some code on here, edited it but when I run the script I return <code>None</code></p>
  <p>Here's the code</p>
  <pre><code>import bs4 as bs
  import sys
  import urllib.request
  from PyQt5.QtWebEngineWidgets import QWebEnginePage
  from PyQt5.QtWidgets import QApplication
  from PyQt5.QtCore import QUrl
  from pprint import pprint
  
  class Page(QWebEnginePage):
      def __init__(self, url):
          self.app = QApplication(sys.argv)
          QWebEnginePage.__init__(self)
          self.html = ''
          self.loadFinished.connect(self._on_load_finished)
          self.load(QUrl(url))
          self.app.exec_()
          
  
      def _on_load_finished(self):
          self.html = self.toHtml(self.Callable)
          print('Load finished')
  
      def Callable(self, html_str):
          self.html = html_str
          self.app.quit()
  
  def main():
      page = Page('https://www.ibm.com/support/fixcentral/swg/selectFixes?parent=IBM%20Security&amp;product=ibm/Information+Management/InfoSphere+Guardium&amp;release=10.0&amp;platform=Linux&amp;function=all')
      soup = bs.BeautifulSoup(page.html, 'html.parser')
      section = soup.find('table', {'id' : 'DataTables_Table_0'})
      pprint (section)
  
  if __name__ == '__main__': main()
  </code></pre>
  <p>Here's the output</p>
  <pre><code>Load finished
  None
  </code></pre>