Returns all the instances that exist for a given parent.  If
        no parent exists, then a blank list will be returned.
        
        :param      parent | <QtGui.QWidget>
        
        :return     [<XView>, ..]

def instances(cls, parent=None):
        """
        Returns all the instances that exist for a given parent.  If
        no parent exists, then a blank list will be returned.
        
        :param      parent | <QtGui.QWidget>
        
        :return     [<XView>, ..]
        """
        if parent is None:
            parent = projexui.topWindow()
        return parent.findChildren(cls)