class_docstr: ToolBar companion class which ensures all buttons have the same size.
code: def minimumSizeHint(self):
      ms = super(ToolButton, self).minimumSizeHint()
      w1, h1 = ms.width(), ms.height()
      w2, h2 = self.minSize
      ToolButton.minSize = max(w1, w2), max(h1, h2)
      return QSize(*ToolButton.minSize)
  
label_desc: Use image node_id 1 for calling the ToolButton obj's underlying member method code with example usage: obj.minimumSizeHint() and returns: QSize