title: PyQt5 get QErrorMessage to block Mainwindow
body: <p>In PyQt5, and I believe retroactively at least to 4, if a QMessageBox is initialized with MainWindow as the parent it will block any input to MainWindow until the MessageBox is accepted, closed, etc...</p>
  
  <p>However, if you initialize a QErrorMessage using MainWindow as parent this behavior does not occur. Is there a way to pass some sort of window parameter to QErrorMessage such that it blocks the parent window until it is closed?</p>
  
  <p>n.b. I realize that I can make a QMessageBox behave and appear like a QErrorMessage. I would just like to know if the above described behavior is possible.</p>