python pyqt5 嵌套布局

def __init__(self):  
    super().__init__()
    self.setWindowTitle('嵌套布局示例')
   
    # 全局布局（1个）：水平
    wlayout =  QHBoxLayout() 
     # 局部布局（4个）：水平、竖直、网格、表单
    hlayout =  QHBoxLayout()
    vlayout =  QVBoxLayout()
    glayout = QGridLayout()
    formlayout =  QFormLayout()
    
    # 局部布局添加部件（例如：按钮）
    hlayout.addWidget( QPushButton(str(1)) ) 
    hlayout.addWidget( QPushButton(str(2)) )
    vlayout.addWidget( QPushButton(str(3)) )
    vlayout.addWidget( QPushButton(str(4)) )
    glayout.addWidget( QPushButton(str(5)) , 0, 0 )
    glayout.addWidget( QPushButton(str(6)) , 0, 1 )
    glayout.addWidget( QPushButton(str(7)) , 1, 0)
    glayout.addWidget( QPushButton(str(8)) , 1, 1)
    formlayout.addWidget( QPushButton(str(9))  )
    formlayout.addWidget( QPushButton(str(10)) )
    formlayout.addWidget( QPushButton(str(11)) )
    formlayout.addWidget( QPushButton(str(12)) )
    
    # 准备四个部件
    hwg =  QWidget() 
    vwg =  QWidget()
    gwg =  QWidget()
    fwg =  QWidget()
            
    # 四个部件设置局部布局
    hwg.setLayout(hlayout) 
    vwg.setLayout(vlayout)
    gwg.setLayout(glayout)
    fwg.setLayout(formlayout)
    
     # 四个部件加至全局布局
    wlayout.addWidget(hwg)
    wlayout.addWidget(vwg)
    wlayout.addWidget(gwg)
    wlayout.addWidget(fwg)
    
    # 窗体本体设置全局布局
    self.setLayout(wlayout)