title: PyQt5 ListWidget add list items
body: <p>while learning PyQt5 i found a little problem( maybe a bug) in the ListWidget Widget (and all other widgets)</p>
  
  <p>the <code>ListWidget</code> have a <code>addItem</code> method overloaded :
  ( the code is in c++ but this is the same interface in pyqt )</p>
  
  <pre><code>void    addItem(const QString &amp;label)
  void    addItem(QListWidgetItem *item)
  void    addItems(const QStringList &amp;labels)
  </code></pre>
  
  <p>so the problem is that in PyQt5 there is no more <code>QStringList</code> type, and i should use a simple list of strings instead of the <code>QStringList</code></p>
  
  <p>but when i receive and error telling me that no method match the given paramaters :</p>
  
  <pre><code>Traceback (most recent call last):
    File "main.py", line 21, in &lt;module&gt;
      listWidget.addItem(ls)
  TypeError: arguments did not match any overloaded call:
    addItem(self, QListWidgetItem): argument 1 has unexpected type 'list'
    addItem(self, str): argument 1 has unexpected type 'list'
  </code></pre>
  
  <p>Here is my code :</p>
  
  <pre><code>from PyQt5 import QtGui, QtCore, QtWidgets
  from PyQt5.QtWidgets import *
  
  import sys
  
  
  if __name__ == '__main__':
  
      app = QApplication(sys.argv)
  
  
      listWidget = QListWidget()
      listWidget.show()
  
      ls = ['test', 'test2', 'test3']
  
      listWidget.addItem('test')
      listWidget.addItem('test2')
      listWidget.addItem('test3')
  
      listWidget.addItem(ls)
  
      sys.exit(app.exec_())
  </code></pre>