title: Qt has no attribute 'AlignCenter'
body: <p>I am using PyQt5 on Python 3.5.</p>
  <p>I want to make a <code>QLabel</code> widget with a centered text. Therefore, I call the <code>setAlignment</code> method with the <code>AlignCenter</code> flag.</p>
  <p>Here is an MWE:</p>
  <pre><code>import sys
  from PyQt5 import QtWidgets, Qt
  
  app = QtWidgets.QApplication(sys.argv)
  
  label = QtWidgets.QLabel()
  label.setAlignment(Qt.AlignCenter)
  </code></pre>
  <p>However, I get the following error:</p>
  <blockquote>
  <p>label.setAlignment(Qt.AlignCenter)</p>
  <p>AttributeError: module 'PyQt5.Qt' has no attribute 'AlignCenter'</p>
  </blockquote>
  <p>But the <code>Qt.AlignCenter</code>, as well as other alignment flags, are referenced in <a href="http://pyqt.sourceforge.net/Docs/PyQt4/qt.html#AlignmentFlag-enum" rel="noreferrer">PyQt's documentation</a>, as well as <a href="http://doc.qt.io/qt-5/qt.html#AlignmentFlag-enum" rel="noreferrer">Qt's documentation</a>.</p>
  <p>What am I doing wrong?</p>