docs: def initGroupStyle(self, useIcons=True, columnCount=None):
          """
          Initialzes this item with a grouping style option.
          """
          flags      = self.flags()
          if flags & QtCore.Qt.ItemIsSelectable:
              flags ^= QtCore.Qt.ItemIsSelectable
              self.setFlags(flags)
          
          if useIcons:
              ico        = QtGui.QIcon(resources.find('img/treeview/triangle_right.png'))
              expand_ico = QtGui.QIcon(resources.find('img/treeview/triangle_down.png'))
              
              self.setIcon(0, ico)
              self.setExpandedIcon(0, expand_ico)
          
          palette = QtGui.QApplication.palette()
          
          line_clr = palette.color(palette.Mid)
          base_clr = palette.color(palette.Button)
          text_clr = palette.color(palette.ButtonText)
          
          gradient = QtGui.QLinearGradient()
          
          gradient.setColorAt(0.00, line_clr)
          gradient.setColorAt(0.03, line_clr)
          gradient.setColorAt(0.04, base_clr.lighter(105))
          gradient.setColorAt(0.25, base_clr)
          gradient.setColorAt(0.96, base_clr.darker(105))
          gradient.setColorAt(0.97, line_clr)
          gradient.setColorAt(1.00, line_clr)
          
          h = self._fixedHeight
          if not h:
              h = self.sizeHint(0).height()
          if not h:
              h = 18
          
          gradient.setStart(0.0, 0.0)
          gradient.setFinalStop(0.0, h)
          
          brush = QtGui.QBrush(gradient)
          
          tree = self.treeWidget()
          columnCount = columnCount or (tree.columnCount() if tree else self.columnCount())
  
          for i in range(columnCount):
              self.setForeground(i, text_clr)
              self.setBackground(i, brush)