class_docstr: State manager for groups of widgets.
  
  WidgetGroup handles common problems that arise when dealing with groups of widgets like a control
  panel:
  - Provide a single place for saving / restoring the state of all widgets in the group
  - Provide a single signal for detecting when any of the widgets have changed
code: def state(self):
      for w in self.uncachedWidgets:
          self.readWidget(w)
      return self.cache.copy()
  
imports: import inspect
  import weakref
  from .Qt import QtCore, QtWidgets
label_desc: Use image node_id 10 for calling the WidgetGroup obj's underlying member method code with example usage: obj.state() and returns: self