code: def add_adapter(widget_class, signal_name, getter, setter, value_type,
                  flavour=None):
      
  
      new_tu = (widget_class, signal_name, getter, setter,
                value_type, flavour)
      for it,tu in enumerate(__def_adapter):
          if issubclass(tu[WIDGET], widget_class):
              # found an insertion point, iteration is over after inserting
              __def_adapter.insert(it, new_tu)
              return
  
      # simply append it
      __def_adapter.append(new_tu)
docs: This function can be used to extend at runtime the set of
      default adapters. If given widget class which is being added is
      already in the default set, it will be substituted by the new one
      until the next removal (see remove_adapter).
  
      @param flavour can be used to differentiate otherwise identical
      entries (None for no flavour).